diff --git a/antarest/matrixstore/repository.py b/antarest/matrixstore/repository.py
index f96e80de67..6301e39c7f 100644
--- a/antarest/matrixstore/repository.py
+++ b/antarest/matrixstore/repository.py
@@ -1,7 +1,7 @@
 import hashlib
 import logging
+import typing as t
 from pathlib import Path
-from typing import List, Optional, Union
 
 import numpy as np
 from filelock import FileLock
@@ -31,19 +31,19 @@ def save(self, matrix_user_metadata: MatrixDataSet) -> MatrixDataSet:
         logger.debug(f"Matrix dataset {matrix_user_metadata.id} for user {matrix_user_metadata.owner_id} saved")
         return matrix_user_metadata
 
-    def get(self, id: str) -> Optional[MatrixDataSet]:
+    def get(self, id: str) -> t.Optional[MatrixDataSet]:
         matrix: MatrixDataSet = db.session.query(MatrixDataSet).get(id)
         return matrix
 
-    def get_all_datasets(self) -> List[MatrixDataSet]:
-        matrix_datasets: List[MatrixDataSet] = db.session.query(MatrixDataSet).all()
+    def get_all_datasets(self) -> t.List[MatrixDataSet]:
+        matrix_datasets: t.List[MatrixDataSet] = db.session.query(MatrixDataSet).all()
         return matrix_datasets
 
     def query(
         self,
-        name: Optional[str],
-        owner: Optional[int] = None,
-    ) -> List[MatrixDataSet]:
+        name: t.Optional[str],
+        owner: t.Optional[int] = None,
+    ) -> t.List[MatrixDataSet]:
         """
         Query a list of MatrixUserMetadata by searching for each one separately if a set of filter match
 
@@ -59,7 +59,7 @@ def query(
             query = query.filter(MatrixDataSet.name.ilike(f"%{name}%"))  # type: ignore
         if owner is not None:
             query = query.filter(MatrixDataSet.owner_id == owner)
-        datasets: List[MatrixDataSet] = query.distinct().all()
+        datasets: t.List[MatrixDataSet] = query.distinct().all()
         return datasets
 
     def delete(self, dataset_id: str) -> None:
@@ -83,7 +83,7 @@ def save(self, matrix: Matrix) -> Matrix:
         logger.debug(f"Matrix {matrix.id} saved")
         return matrix
 
-    def get(self, matrix_hash: str) -> Optional[Matrix]:
+    def get(self, matrix_hash: str) -> t.Optional[Matrix]:
         matrix: Matrix = db.session.query(Matrix).get(matrix_hash)
         return matrix
 
@@ -130,6 +130,7 @@ def get(self, matrix_hash: str) -> MatrixContent:
 
         matrix_file = self.bucket_dir.joinpath(f"{matrix_hash}.tsv")
         matrix = np.loadtxt(matrix_file, delimiter="\t", dtype=np.float64, ndmin=2)
+        matrix = matrix.reshape((1, 0)) if matrix.size == 0 else matrix
         data = matrix.tolist()
         index = list(range(matrix.shape[0]))
         columns = list(range(matrix.shape[1]))
@@ -148,7 +149,7 @@ def exists(self, matrix_hash: str) -> bool:
         matrix_file = self.bucket_dir.joinpath(f"{matrix_hash}.tsv")
         return matrix_file.exists()
 
-    def save(self, content: Union[List[List[MatrixData]], npt.NDArray[np.float64]]) -> str:
+    def save(self, content: t.Union[t.List[t.List[MatrixData]], npt.NDArray[np.float64]]) -> str:
         """
         Saves the content of a matrix as a TSV file in the bucket directory
         and returns its SHA256 hash.
@@ -188,8 +189,12 @@ def save(self, content: Union[List[List[MatrixData]], npt.NDArray[np.float64]])
             # Ensure exclusive access to the matrix file between multiple processes (or threads).
             lock_file = matrix_file.with_suffix(".tsv.lock")
             with FileLock(lock_file, timeout=15):
-                # noinspection PyTypeChecker
-                np.savetxt(matrix_file, matrix, delimiter="\t", fmt="%.18f")
+                if matrix.size == 0:
+                    # If the array or dataframe is empty, create an empty file instead of
+                    # traditional saving to avoid unwanted line breaks.
+                    open(matrix_file, mode="wb").close()
+                else:
+                    np.savetxt(matrix_file, matrix, delimiter="\t", fmt="%.18f")
 
             # IMPORTANT: Deleting the lock file under Linux can make locking unreliable.
             # See https://github.com/tox-dev/py-filelock/issues/31
diff --git a/antarest/matrixstore/service.py b/antarest/matrixstore/service.py
index c20b0197dc..639084b587 100644
--- a/antarest/matrixstore/service.py
+++ b/antarest/matrixstore/service.py
@@ -1,12 +1,13 @@
 import contextlib
+import io
+import json
 import logging
 import tempfile
+import zipfile
 from abc import ABC, abstractmethod
 from datetime import datetime, timezone
-from io import BytesIO
 from pathlib import Path
 from typing import List, Optional, Sequence, Tuple, Union
-from zipfile import ZipFile
 
 import numpy as np
 from fastapi import UploadFile
@@ -36,6 +37,18 @@
 )
 from antarest.matrixstore.repository import MatrixContentRepository, MatrixDataSetRepository, MatrixRepository
 
+# List of files to exclude from ZIP archives
+EXCLUDED_FILES = {
+    "__MACOSX",
+    ".DS_Store",
+    "._.DS_Store",
+    "Thumbs.db",
+    "desktop.ini",
+    "$RECYCLE.BIN",
+    "System Volume Information",
+    "RECYCLER",
+}
+
 logger = logging.getLogger(__name__)
 
 
@@ -150,29 +163,42 @@ def create(self, data: Union[List[List[MatrixData]], npt.NDArray[np.float64]]) -
             self.repo.save(matrix)
         return matrix_id
 
-    def create_by_importation(self, file: UploadFile, json: bool = False) -> List[MatrixInfoDTO]:
+    def create_by_importation(self, file: UploadFile, is_json: bool = False) -> List[MatrixInfoDTO]:
+        """
+        Imports a matrix from a TSV or JSON file or a collection of matrices from a ZIP file.
+
+        TSV-formatted files are expected to contain only matrix data without any header.
+
+        JSON-formatted files are expected to contain the following attributes:
+
+        - `index`: The list of row labels.
+        - `columns`: The list of column labels.
+        - `data`: The matrix data as a nested list of floats.
+
+        Args:
+            file: The file to import (TSV, JSON or ZIP).
+            is_json: Flag indicating if the file is JSON-encoded.
+
+        Returns:
+            A list of `MatrixInfoDTO` objects containing the SHA256 hash of the imported matrices.
+        """
         with file.file as f:
             if file.content_type == "application/zip":
-                input_zip = ZipFile(BytesIO(f.read()))
-                files = {
-                    info.filename: input_zip.read(info.filename) for info in input_zip.infolist() if not info.is_dir()
-                }
+                with contextlib.closing(f):
+                    buffer = io.BytesIO(f.read())
                 matrix_info: List[MatrixInfoDTO] = []
-                for name in files:
-                    if all(
-                        [
-                            not name.startswith("__MACOSX/"),
-                            not name.startswith(".DS_Store"),
-                        ]
-                    ):
-                        matrix_id = self._file_importation(files[name], json)
-                        matrix_info.append(MatrixInfoDTO(id=matrix_id, name=name))
+                with zipfile.ZipFile(buffer) as zf:
+                    for info in zf.infolist():
+                        if info.is_dir() or info.filename in EXCLUDED_FILES:
+                            continue
+                        matrix_id = self._file_importation(zf.read(info.filename), is_json=is_json)
+                        matrix_info.append(MatrixInfoDTO(id=matrix_id, name=info.filename))
                 return matrix_info
             else:
-                matrix_id = self._file_importation(f.read(), json)
+                matrix_id = self._file_importation(f.read(), is_json=is_json)
                 return [MatrixInfoDTO(id=matrix_id, name=file.filename)]
 
-    def _file_importation(self, file: bytes, is_json: bool = False) -> str:
+    def _file_importation(self, file: bytes, *, is_json: bool = False) -> str:
         """
         Imports a matrix from a TSV or JSON file in bytes format.
 
@@ -184,9 +210,12 @@ def _file_importation(self, file: bytes, is_json: bool = False) -> str:
             A SHA256 hash that identifies the imported matrix.
         """
         if is_json:
-            return self.create(MatrixContent.parse_raw(file).data)
+            obj = json.loads(file)
+            content = MatrixContent(**obj)
+            return self.create(content.data)
         # noinspection PyTypeChecker
-        matrix = np.loadtxt(BytesIO(file), delimiter="\t", dtype=np.float64, ndmin=2)
+        matrix = np.loadtxt(io.BytesIO(file), delimiter="\t", dtype=np.float64, ndmin=2)
+        matrix = matrix.reshape((1, 0)) if matrix.size == 0 else matrix
         return self.create(matrix)
 
     def get_dataset(
@@ -380,8 +409,13 @@ def create_matrix_files(self, matrix_ids: Sequence[str], export_path: Path) -> s
                 name = f"matrix-{mtx.id}.txt"
                 filepath = f"{tmpdir}/{name}"
                 array = np.array(mtx.data, dtype=np.float64)
-                # noinspection PyTypeChecker
-                np.savetxt(filepath, array, delimiter="\t", fmt="%.18f")
+                if array.size == 0:
+                    # If the array or dataframe is empty, create an empty file instead of
+                    # traditional saving to avoid unwanted line breaks.
+                    open(filepath, mode="wb").close()
+                else:
+                    # noinspection PyTypeChecker
+                    np.savetxt(filepath, array, delimiter="\t", fmt="%.18f")
             zip_dir(Path(tmpdir), export_path)
             stopwatch.log_elapsed(lambda x: logger.info(f"Matrix dataset exported (zipped mode) in {x}s"))
         return str(export_path)
@@ -467,5 +501,10 @@ def download_matrix(
             raise UserHasNotPermissionError()
         if matrix := self.get(matrix_id):
             array = np.array(matrix.data, dtype=np.float64)
-            # noinspection PyTypeChecker
-            np.savetxt(filepath, array, delimiter="\t", fmt="%.18f")
+            if array.size == 0:
+                # If the array or dataframe is empty, create an empty file instead of
+                # traditional saving to avoid unwanted line breaks.
+                open(filepath, mode="wb").close()
+            else:
+                # noinspection PyTypeChecker
+                np.savetxt(filepath, array, delimiter="\t", fmt="%.18f")
diff --git a/antarest/matrixstore/uri_resolver_service.py b/antarest/matrixstore/uri_resolver_service.py
index a13d6c6ad0..01717c57bd 100644
--- a/antarest/matrixstore/uri_resolver_service.py
+++ b/antarest/matrixstore/uri_resolver_service.py
@@ -11,7 +11,7 @@ class UriResolverService:
     def __init__(self, matrix_service: ISimpleMatrixService):
         self.matrix_service = matrix_service
 
-    def resolve(self, uri: str, formatted: bool = True) -> Optional[SUB_JSON]:
+    def resolve(self, uri: str, formatted: bool = True) -> SUB_JSON:
         res = UriResolverService._extract_uri_components(uri)
         if res:
             protocol, uuid = res
@@ -52,19 +52,17 @@ def _resolve_matrix(self, id: str, formatted: bool = True) -> SUB_JSON:
                     index=data.index,
                     columns=data.columns,
                 )
-                if not df.empty:
-                    return (
-                        df.to_csv(
-                            None,
-                            sep="\t",
-                            header=False,
-                            index=False,
-                            float_format="%.6f",
-                        )
-                        or ""
-                    )
-                else:
+                if df.empty:
                     return ""
+                else:
+                    csv = df.to_csv(
+                        None,
+                        sep="\t",
+                        header=False,
+                        index=False,
+                        float_format="%.6f",
+                    )
+                    return csv or ""
         raise ValueError(f"id matrix {id} not found")
 
     def build_matrix_uri(self, id: str) -> str:
diff --git a/antarest/matrixstore/web.py b/antarest/matrixstore/web.py
index a97ae7d45b..4b47135b52 100644
--- a/antarest/matrixstore/web.py
+++ b/antarest/matrixstore/web.py
@@ -55,7 +55,7 @@ def create_by_importation(
     ) -> Any:
         logger.info("Importing new matrix dataset", extra={"user": current_user.id})
         if current_user.id is not None:
-            return service.create_by_importation(file, json)
+            return service.create_by_importation(file, is_json=json)
         raise UserHasNotPermissionError()
 
     @bp.get("/matrix/{id}", tags=[APITag.matrix], response_model=MatrixDTO)
diff --git a/antarest/study/service.py b/antarest/study/service.py
index 332fc384da..b9ec491c18 100644
--- a/antarest/study/service.py
+++ b/antarest/study/service.py
@@ -1378,6 +1378,7 @@ def _create_edit_study_command(
             if isinstance(data, bytes):
                 # noinspection PyTypeChecker
                 matrix = np.loadtxt(io.BytesIO(data), delimiter="\t", dtype=np.float64, ndmin=2)
+                matrix = matrix.reshape((1, 0)) if matrix.size == 0 else matrix
                 return ReplaceMatrix(
                     target=url,
                     matrix=matrix.tolist(),
diff --git a/antarest/study/storage/rawstudy/model/filesystem/matrix/output_series_matrix.py b/antarest/study/storage/rawstudy/model/filesystem/matrix/output_series_matrix.py
index 13ea8e0400..6f82eaab34 100644
--- a/antarest/study/storage/rawstudy/model/filesystem/matrix/output_series_matrix.py
+++ b/antarest/study/storage/rawstudy/model/filesystem/matrix/output_series_matrix.py
@@ -98,15 +98,16 @@ def _dump_json(self, data: JSON) -> None:
         matrix = pd.concat([time, matrix], axis=1)
 
         head = self.head_writer.build(var=df.columns.size, end=df.index.size)
-        self.config.path.write_text(head)
-
-        matrix.to_csv(
-            open(self.config.path, "a", newline="\n"),
-            sep="\t",
-            index=False,
-            header=False,
-            line_terminator="\n",
-        )
+        with self.config.path.open(mode="w", newline="\n") as fd:
+            fd.write(head)
+            if not matrix.empty:
+                matrix.to_csv(
+                    fd,
+                    sep="\t",
+                    header=False,
+                    index=False,
+                    float_format="%.6f",
+                )
 
     def check_errors(
         self,
diff --git a/antarest/tools/lib.py b/antarest/tools/lib.py
index b27e4dcee4..2d2953e3f5 100644
--- a/antarest/tools/lib.py
+++ b/antarest/tools/lib.py
@@ -77,6 +77,7 @@ def apply_commands(
         matrix_dataset: List[str] = []
         for matrix_file in matrices_dir.iterdir():
             matrix = np.loadtxt(matrix_file, delimiter="\t", dtype=np.float64, ndmin=2)
+            matrix = matrix.reshape((1, 0)) if matrix.size == 0 else matrix
             matrix_data = matrix.tolist()
             res = self.session.post(self.build_url("/v1/matrix"), json=matrix_data)
             res.raise_for_status()
diff --git a/tests/matrixstore/test_repository.py b/tests/matrixstore/test_repository.py
index 9d1254953a..3973a18d39 100644
--- a/tests/matrixstore/test_repository.py
+++ b/tests/matrixstore/test_repository.py
@@ -1,9 +1,10 @@
+import typing as t
 from datetime import datetime
 from pathlib import Path
-from typing import Optional
 
 import numpy as np
 import pytest
+from numpy import typing as npt
 
 from antarest.core.config import Config, SecurityConfig
 from antarest.core.utils.fastapi_sqlalchemy import db
@@ -12,16 +13,15 @@
 from antarest.matrixstore.model import Matrix, MatrixContent, MatrixDataSet, MatrixDataSetRelation
 from antarest.matrixstore.repository import MatrixContentRepository, MatrixDataSetRepository, MatrixRepository
 
+ArrayData = t.Union[t.List[t.List[float]], npt.NDArray[np.float64]]
+
 
 class TestMatrixRepository:
-    def test_db_lifecycle(self):
+    def test_db_lifecycle(self) -> None:
         with db():
             # sourcery skip: extract-method
             repo = MatrixRepository()
-            m = Matrix(
-                id="hello",
-                created_at=datetime.now(),
-            )
+            m = Matrix(id="hello", created_at=datetime.now())
             repo.save(m)
             assert m.id
             assert m == repo.get(m.id)
@@ -29,11 +29,11 @@ def test_db_lifecycle(self):
             repo.delete(m.id)
             assert repo.get(m.id) is None
 
-    def test_bucket_lifecycle(self, tmp_path: Path):
+    def test_bucket_lifecycle(self, tmp_path: Path) -> None:
         repo = MatrixContentRepository(tmp_path)
 
-        a = [[1, 2], [3, 4]]
-        b = [[5, 6], [7, 8]]
+        a: ArrayData = [[1, 2], [3, 4]]
+        b: ArrayData = [[5, 6], [7, 8]]
 
         matrix_content_a = MatrixContent(data=a, index=[0, 1], columns=[0, 1])
         matrix_content_b = MatrixContent(data=b, index=[0, 1], columns=[0, 1])
@@ -51,7 +51,7 @@ def test_bucket_lifecycle(self, tmp_path: Path):
         with pytest.raises(FileNotFoundError):
             repo.get(aid)
 
-    def test_dataset(self):
+    def test_dataset(self) -> None:
         with db():
             # sourcery skip: extract-duplicate-method, extract-method
             repo = MatrixRepository()
@@ -66,15 +66,9 @@ def test_dataset(self):
 
             dataset_repo = MatrixDataSetRepository()
 
-            m1 = Matrix(
-                id="hello",
-                created_at=datetime.now(),
-            )
+            m1 = Matrix(id="hello", created_at=datetime.now())
             repo.save(m1)
-            m2 = Matrix(
-                id="world",
-                created_at=datetime.now(),
-            )
+            m2 = Matrix(id="world", created_at=datetime.now())
             repo.save(m2)
 
             dataset = MatrixDataSet(
@@ -94,7 +88,7 @@ def test_dataset(self):
             dataset.matrices.append(matrix_relation)
 
             dataset = dataset_repo.save(dataset)
-            dataset_query_result: Optional[MatrixDataSet] = dataset_repo.get(dataset.id)
+            dataset_query_result = dataset_repo.get(dataset.id)
             assert dataset_query_result is not None
             assert dataset_query_result.name == "some name"
             assert len(dataset_query_result.matrices) == 2
@@ -106,12 +100,12 @@ def test_dataset(self):
                 updated_at=datetime.now(),
             )
             dataset_repo.save(dataset_update)
-            dataset_query_result: Optional[MatrixDataSet] = dataset_repo.get(dataset.id)
+            dataset_query_result = dataset_repo.get(dataset.id)
             assert dataset_query_result is not None
             assert dataset_query_result.name == "some name change"
             assert dataset_query_result.owner_id == user.id
 
-    def test_datastore_query(self):
+    def test_datastore_query(self) -> None:
         # sourcery skip: extract-duplicate-method
         with db():
             user_repo = UserRepository(Config(security=SecurityConfig()))
@@ -121,15 +115,9 @@ def test_datastore_query(self):
             user2 = user_repo.save(User(name="hello", password=Password("world")))
 
             repo = MatrixRepository()
-            m1 = Matrix(
-                id="hello",
-                created_at=datetime.now(),
-            )
+            m1 = Matrix(id="hello", created_at=datetime.now())
             repo.save(m1)
-            m2 = Matrix(
-                id="world",
-                created_at=datetime.now(),
-            )
+            m2 = Matrix(id="world", created_at=datetime.now())
             repo.save(m2)
 
             dataset_repo = MatrixDataSetRepository()
@@ -176,14 +164,19 @@ def test_datastore_query(self):
             assert repo.get(m1.id) is not None
             assert (
                 len(
-                    db.session.query(MatrixDataSetRelation).filter(MatrixDataSetRelation.dataset_id == dataset.id).all()
+                    # fmt: off
+                    db.session
+                    .query(MatrixDataSetRelation)
+                    .filter(MatrixDataSetRelation.dataset_id == dataset.id)
+                    .all()
+                    # fmt: on
                 )
                 == 0
             )
 
 
 class TestMatrixContentRepository:
-    def test_save(self, matrix_content_repo: MatrixContentRepository):
+    def test_save(self, matrix_content_repo: MatrixContentRepository) -> None:
         """
         Saves the content of a matrix as a TSV file in the directory
         and returns its SHA256 hash.
@@ -192,6 +185,7 @@ def test_save(self, matrix_content_repo: MatrixContentRepository):
         bucket_dir = matrix_content_repo.bucket_dir
 
         # when the data is saved in the repo
+        data: ArrayData
         data = [[1, 2, 3], [4, 5, 6]]
         matrix_hash = matrix_content_repo.save(data)
         # then a TSV file is created in the repo directory
@@ -224,12 +218,37 @@ def test_save(self, matrix_content_repo: MatrixContentRepository):
         other_matrix_file = bucket_dir.joinpath(f"{other_matrix_hash}.tsv")
         assert set(matrix_files) == {matrix_file, other_matrix_file}
 
-    def test_get(self, matrix_content_repo):
+    def test_save_and_retrieve_empty_matrix(self, matrix_content_repo: MatrixContentRepository) -> None:
+        """
+        Test saving and retrieving empty matrices as TSV files.
+        Il all cases the file must be empty.
+        """
+        bucket_dir = matrix_content_repo.bucket_dir
+
+        # Test with an empty matrix
+        empty_array: ArrayData = []
+        matrix_hash = matrix_content_repo.save(empty_array)
+        matrix_file = bucket_dir.joinpath(f"{matrix_hash}.tsv")
+        retrieved_matrix = matrix_content_repo.get(matrix_hash)
+
+        assert not matrix_file.read_bytes()
+        assert retrieved_matrix.data == [[]]
+
+        # Test with an empty 2D array
+        empty_2d_array: ArrayData = [[]]
+        matrix_hash = matrix_content_repo.save(empty_2d_array)
+        matrix_file = bucket_dir.joinpath(f"{matrix_hash}.tsv")
+        retrieved_matrix = matrix_content_repo.get(matrix_hash)
+
+        assert not matrix_file.read_bytes()
+        assert retrieved_matrix.data == [[]]
+
+    def test_get(self, matrix_content_repo: MatrixContentRepository) -> None:
         """
         Retrieves the content of a matrix with a given SHA256 hash.
         """
         # when the data is saved in the repo
-        data = [[1, 2, 3], [4, 5, 6]]
+        data: ArrayData = [[1, 2, 3], [4, 5, 6]]
         matrix_hash = matrix_content_repo.save(data)
         # then the saved matrix object can be retrieved
         content = matrix_content_repo.get(matrix_hash)
@@ -243,12 +262,12 @@ def test_get(self, matrix_content_repo):
             missing_hash = "8b1a9953c4611296a827abf8c47804d7e6c49c6b"
             matrix_content_repo.get(missing_hash)
 
-    def test_exists(self, matrix_content_repo):
+    def test_exists(self, matrix_content_repo: MatrixContentRepository) -> None:
         """
         Checks if a matrix with a given SHA256 hash exists in the directory.
         """
         # when the data is saved in the repo
-        data = [[1, 2, 3], [4, 5, 6]]
+        data: ArrayData = [[1, 2, 3], [4, 5, 6]]
         matrix_hash = matrix_content_repo.save(data)
         # then the saved matrix object exists
         assert matrix_content_repo.exists(matrix_hash)
@@ -258,12 +277,12 @@ def test_exists(self, matrix_content_repo):
         missing_hash = "8b1a9953c4611296a827abf8c47804d7e6c49c6b"
         assert not matrix_content_repo.exists(missing_hash)
 
-    def test_delete(self, matrix_content_repo):
+    def test_delete(self, matrix_content_repo: MatrixContentRepository) -> None:
         """
         Deletes the tsv file containing the content of a matrix with a given SHA256 hash.
         """
         # when the data is saved in the repo
-        data = [[1, 2, 3], [4, 5, 6]]
+        data: ArrayData = [[1, 2, 3], [4, 5, 6]]
         matrix_hash = matrix_content_repo.save(data)
         # then the saved matrix object can be deleted
         matrix_content_repo.delete(matrix_hash)
diff --git a/tests/matrixstore/test_service.py b/tests/matrixstore/test_service.py
index a251cda4c5..db26e6403a 100644
--- a/tests/matrixstore/test_service.py
+++ b/tests/matrixstore/test_service.py
@@ -1,9 +1,10 @@
 import datetime
 import io
+import json
 import time
 import typing as t
+import zipfile
 from unittest.mock import ANY, Mock
-from zipfile import ZIP_DEFLATED, ZipFile
 
 import numpy as np
 import pytest
@@ -26,12 +27,14 @@
 )
 from antarest.matrixstore.service import MatrixService
 
+MatrixType = t.List[t.List[float]]
+
 
 class TestMatrixService:
-    def test_create__nominal_case(self, matrix_service: MatrixService):
+    def test_create__nominal_case(self, matrix_service: MatrixService) -> None:
         """Creates a new matrix object with the specified data."""
         # when a matrix is created (inserted) in the service
-        data = [[1, 2, 3], [4, 5, 6]]
+        data: MatrixType = [[1, 2, 3], [4, 5, 6]]
         matrix_id = matrix_service.create(data)
 
         # A "real" hash value is calculated
@@ -52,7 +55,7 @@ def test_create__nominal_case(self, matrix_service: MatrixService):
         now = datetime.datetime.utcnow()
         assert now - datetime.timedelta(seconds=1) <= obj.created_at <= now
 
-    def test_create__from_numpy_array(self, matrix_service: MatrixService):
+    def test_create__from_numpy_array(self, matrix_service: MatrixService) -> None:
         """Creates a new matrix object with the specified data."""
         # when a matrix is created (inserted) in the service
         data = np.array([[1, 2, 3], [4, 5, 6]], dtype=np.float64)
@@ -76,13 +79,13 @@ def test_create__from_numpy_array(self, matrix_service: MatrixService):
         now = datetime.datetime.utcnow()
         assert now - datetime.timedelta(seconds=1) <= obj.created_at <= now
 
-    def test_create__side_effect(self, matrix_service: MatrixService):
+    def test_create__side_effect(self, matrix_service: MatrixService) -> None:
         """Creates a new matrix object with the specified data, but fail during saving."""
         # if the matrix can't be created in the service
         matrix_repo = matrix_service.repo
         matrix_repo.save = Mock(side_effect=Exception("database error"))
         with pytest.raises(Exception, match="database error"):
-            data = [[1, 2, 3], [4, 5, 6]]
+            data: MatrixType = [[1, 2, 3], [4, 5, 6]]
             matrix_service.create(data)
 
         # the associated matrix file must not be deleted
@@ -94,10 +97,10 @@ def test_create__side_effect(self, matrix_service: MatrixService):
         with db():
             assert not db.session.query(Matrix).count()
 
-    def test_get(self, matrix_service):
+    def test_get(self, matrix_service: MatrixService) -> None:
         """Get a matrix object from the database and the matrix content repository."""
         # when a matrix is created (inserted) in the service
-        data = [[1, 2, 3], [4, 5, 6]]
+        data: MatrixType = [[1, 2, 3], [4, 5, 6]]
         matrix_id = matrix_service.create(data)
 
         # nominal_case: we can retrieve the matrix and its content
@@ -120,10 +123,10 @@ def test_get(self, matrix_service):
             obj = matrix_service.get(missing_hash)
         assert obj is None
 
-    def test_exists(self, matrix_service):
+    def test_exists(self, matrix_service: MatrixService) -> None:
         """Test the exists method."""
         # when a matrix is created (inserted) in the service
-        data = [[1, 2, 3], [4, 5, 6]]
+        data: MatrixType = [[1, 2, 3], [4, 5, 6]]
         matrix_id = matrix_service.create(data)
 
         # nominal_case: we can retrieve the matrix and its content
@@ -132,10 +135,10 @@ def test_exists(self, matrix_service):
             missing_hash = "8b1a9953c4611296a827abf8c47804d7e6c49c6b"
             assert not matrix_service.exists(missing_hash)
 
-    def test_delete__nominal_case(self, matrix_service: MatrixService):
+    def test_delete__nominal_case(self, matrix_service: MatrixService) -> None:
         """Delete a matrix object from the matrix content repository and the database."""
         # when a matrix is created (inserted) in the service
-        data = [[1, 2, 3], [4, 5, 6]]
+        data: MatrixType = [[1, 2, 3], [4, 5, 6]]
         matrix_id = matrix_service.create(data)
 
         # When the matrix id deleted
@@ -151,7 +154,7 @@ def test_delete__nominal_case(self, matrix_service: MatrixService):
         with db():
             assert not db.session.query(Matrix).count()
 
-    def test_delete__missing(self, matrix_service: MatrixService):
+    def test_delete__missing(self, matrix_service: MatrixService) -> None:
         """Delete a matrix object from the matrix content repository and the database."""
         # When the matrix id deleted
         with db():
@@ -167,8 +170,139 @@ def test_delete__missing(self, matrix_service: MatrixService):
         with db():
             assert not db.session.query(Matrix).count()
 
+    @pytest.mark.parametrize(
+        "data",
+        [
+            pytest.param([[1, 2, 3], [4, 5, 6]], id="classic-array"),
+            pytest.param([[]], id="2D-empty-array"),
+        ],
+    )
+    @pytest.mark.parametrize("content_type", ["application/json", "text/plain"])
+    def test_create_by_importation__nominal_case(
+        self,
+        matrix_service: MatrixService,
+        data: MatrixType,
+        content_type: str,
+    ) -> None:
+        """
+        Create a new matrix by importing a file.
+        The file is either a JSON file or a TSV file.
+        """
+        # Prepare the matrix data to import
+        matrix = np.array(data, dtype=np.float64)
+        if content_type == "application/json":
+            # JSON format of the array using the dataframe format
+            index = list(range(matrix.shape[0]))
+            columns = list(range(matrix.shape[1]))
+            content = json.dumps({"index": index, "columns": columns, "data": matrix.tolist()})
+            buffer = io.BytesIO(content.encode("utf-8"))
+            filename = "matrix.json"
+            json_format = True
+        else:
+            # TSV format of the array (without header)
+            buffer = io.BytesIO()
+            np.savetxt(buffer, matrix, delimiter="\t")
+            buffer.seek(0)
+            filename = "matrix.txt"
+            json_format = False
+
+        # Prepare a UploadFile object using the buffer
+        upload_file = _create_upload_file(filename=filename, file=buffer, content_type=content_type)
+
+        # when a matrix is created (inserted) in the service
+        info_list: t.Sequence[MatrixInfoDTO] = matrix_service.create_by_importation(upload_file, is_json=json_format)
+
+        # Then, check the list of created matrices
+        assert len(info_list) == 1
+        info = info_list[0]
 
-def test_dataset_lifecycle():
+        # A "real" hash value is calculated
+        assert info.id, "ID can't be empty"
+
+        # The matrix is saved in the content repository as a TSV file
+        bucket_dir = matrix_service.matrix_content_repository.bucket_dir
+        content_path = bucket_dir.joinpath(f"{info.id}.tsv")
+        actual = np.loadtxt(content_path)
+        assert actual.all() == matrix.all()
+
+        # A matrix object is stored in the database
+        with db():
+            obj = matrix_service.repo.get(info.id)
+        assert obj is not None, f"Missing Matrix object {info.id}"
+        assert obj.width == matrix.shape[1]
+        assert obj.height == matrix.shape[0]
+        now = datetime.datetime.utcnow()
+        assert now - datetime.timedelta(seconds=1) <= obj.created_at <= now
+
+    @pytest.mark.parametrize("content_type", ["application/json", "text/plain"])
+    def test_create_by_importation__zip_file(self, matrix_service: MatrixService, content_type: str) -> None:
+        """
+        Create a ZIP file with several matrices, using either a JSON format or a TSV format.
+        All matrices of the ZIP file use the same format.
+        Check that the matrices are correctly imported.
+        """
+        # Prepare the matrix data to import
+        data_list: t.List[MatrixType] = [
+            [[1, 2, 3], [4, 5, 6]],
+            [[7, 8, 9, 10, 11], [17, 18, 19, 20, 21], [27, 28, 29, 30, 31]],
+            [[]],
+        ]
+        matrix_list: t.List[np.ndarray] = [np.array(data, dtype=np.float64) for data in data_list]
+        if content_type == "application/json":
+            # JSON format of the array using the dataframe format
+            index_list = [list(range(matrix.shape[0])) for matrix in matrix_list]
+            columns_list = [list(range(matrix.shape[1])) for matrix in matrix_list]
+            data_list = [matrix.tolist() for matrix in matrix_list]
+            content_list = [
+                json.dumps({"index": index, "columns": columns, "data": data}).encode("utf-8")
+                for index, columns, data in zip(index_list, columns_list, data_list)
+            ]
+            json_format = True
+        else:
+            # TSV format of the array (without header)
+            content_list = []
+            for matrix in matrix_list:
+                buffer = io.BytesIO()
+                np.savetxt(buffer, matrix, delimiter="\t")
+                content_list.append(buffer.getvalue())
+            json_format = False
+
+        buffer = io.BytesIO()
+        with zipfile.ZipFile(buffer, mode="w", compression=zipfile.ZIP_DEFLATED) as zf:
+            for i, content in enumerate(content_list):
+                suffix = {True: "json", False: "txt"}[json_format]
+                zf.writestr(f"matrix-{i:1d}.{suffix}", content)
+        buffer.seek(0)
+
+        # Prepare a UploadFile object using the buffer
+        upload_file = _create_upload_file(filename="matrices.zip", file=buffer, content_type="application/zip")
+
+        # When matrices are created (inserted) in the service
+        info_list: t.Sequence[MatrixInfoDTO] = matrix_service.create_by_importation(upload_file, is_json=json_format)
+
+        # Then, check the list of created matrices
+        assert len(info_list) == len(data_list)
+        for info, matrix in zip(info_list, matrix_list):
+            # A "real" hash value is calculated
+            assert info.id, "ID can't be empty"
+
+            # The matrix is saved in the content repository as a TSV file
+            bucket_dir = matrix_service.matrix_content_repository.bucket_dir
+            content_path = bucket_dir.joinpath(f"{info.id}.tsv")
+            actual = np.loadtxt(content_path)
+            assert actual.all() == matrix.all()
+
+            # A matrix object is stored in the database
+            with db():
+                obj = matrix_service.repo.get(info.id)
+            assert obj is not None, f"Missing Matrix object {info.id}"
+            assert obj.width == (matrix.shape[1] if matrix.size else 0)
+            assert obj.height == matrix.shape[0]
+            now = datetime.datetime.utcnow()
+            assert now - datetime.timedelta(seconds=1) <= obj.created_at <= now
+
+
+def test_dataset_lifecycle() -> None:
     content = Mock()
     repo = Mock()
     dataset_repo = Mock()
@@ -347,7 +481,7 @@ def test_dataset_lifecycle():
     dataset_repo.delete.assert_called_once()
 
 
-def _create_upload_file(filename: str, file: t.IO = None, content_type: str = "") -> UploadFile:
+def _create_upload_file(filename: str, file: io.BytesIO, content_type: str = "") -> UploadFile:
     if hasattr(UploadFile, "content_type"):
         # `content_type` attribute was replace by a read-ony property in starlette-v0.24.
         headers = Headers(headers={"content-type": content_type})
@@ -356,54 +490,3 @@ def _create_upload_file(filename: str, file: t.IO = None, content_type: str = ""
     else:
         # noinspection PyTypeChecker,PyArgumentList
         return UploadFile(filename=filename, file=file, content_type=content_type)
-
-
-def test_import():
-    # Init Mock
-    repo_content = Mock()
-    repo = Mock()
-
-    file_str = "1\t2\t3\t4\t5\n6\t7\t8\t9\t10"
-    matrix_content = str.encode(file_str)
-
-    # Expected
-    matrix_id = "123"
-    exp_matrix_info = [MatrixInfoDTO(id=matrix_id, name="matrix.txt")]
-    exp_matrix = Matrix(id=matrix_id, width=5, height=2)
-    # Test
-    service = MatrixService(
-        repo=repo,
-        repo_dataset=Mock(),
-        matrix_content_repository=repo_content,
-        file_transfer_manager=Mock(),
-        task_service=Mock(),
-        config=Mock(),
-        user_service=Mock(),
-    )
-    service.repo.get.return_value = None
-    service.matrix_content_repository.save.return_value = matrix_id
-    service.repo.save.return_value = exp_matrix
-
-    # CSV importation
-    matrix_file = _create_upload_file(
-        filename="matrix.txt",
-        file=io.BytesIO(matrix_content),
-        content_type="test/plain",
-    )
-    matrix = service.create_by_importation(matrix_file)
-    assert matrix[0].name == exp_matrix_info[0].name
-    assert matrix[0].id is not None
-
-    # Zip importation
-    zip_content = io.BytesIO()
-    with ZipFile(zip_content, "w", ZIP_DEFLATED) as output_data:
-        output_data.writestr("matrix.txt", file_str)
-
-    zip_content.seek(0)
-    zip_file = _create_upload_file(
-        filename="Matrix.zip",
-        file=zip_content,
-        content_type="application/zip",
-    )
-    matrix = service.create_by_importation(zip_file)
-    assert matrix == exp_matrix_info
diff --git a/tests/storage/repository/filesystem/matrix/output_series_matrix_test.py b/tests/storage/repository/filesystem/matrix/output_series_matrix_test.py
index e93b0006f8..d739e73b0d 100644
--- a/tests/storage/repository/filesystem/matrix/output_series_matrix_test.py
+++ b/tests/storage/repository/filesystem/matrix/output_series_matrix_test.py
@@ -9,7 +9,7 @@
 from antarest.study.storage.rawstudy.model.filesystem.matrix.output_series_matrix import OutputSeriesMatrix
 
 MATRIX_DAILY_DATA = """\
-DE	area	va	hourly
+DE\tarea\tva\thourly
 \tVARIABLES\tBEGIN\tEND
 \t2\t1\t2
 
@@ -21,7 +21,7 @@
 """
 
 
-def test_get(tmp_path: Path):
+def test_get(tmp_path: Path) -> None:
     file = tmp_path / "matrix-daily.txt"
     file.write_text("\n\n\n\nmock\tfile\ndummy\tdummy\ndummy\tdummy\ndummy\tdummy")
     config = FileStudyTreeConfig(study_path=file, path=file, study_id="id", version=-1)
@@ -55,7 +55,7 @@ def test_get(tmp_path: Path):
     assert node.load() == matrix.to_dict(orient="split")
 
 
-def test_save(tmp_path: Path):
+def test_save(tmp_path: Path) -> None:
     file = tmp_path / "matrix-daily.txt"
     config = FileStudyTreeConfig(study_path=file, path=file, study_id="id", version=-1)