diff --git a/cozy/architecture/observable.py b/cozy/architecture/observable.py
index 5aa6e833..9380d4f7 100644
--- a/cozy/architecture/observable.py
+++ b/cozy/architecture/observable.py
@@ -33,7 +33,7 @@ def remove_bind(self, prop: str, callback: Callable):
             if callback in self._observers[prop]:
                 self._observers[prop].remove(callback)
             else:
-                log.info("Callback not found in prop's {} observers. Skipping remove bind...".format(prop))
+                log.info("Callback not found in prop's %s observers. Skipping remove bind...", prop)
         else:
             log.info("Prop not found in observers. Skipping remove bind...")
 
diff --git a/cozy/control/artwork_cache.py b/cozy/control/artwork_cache.py
index 462e7ddd..e2bbdf23 100644
--- a/cozy/control/artwork_cache.py
+++ b/cozy/control/artwork_cache.py
@@ -129,7 +129,7 @@ def _load_pixbuf_from_cache(self, book, size):
             else:
                 pixbuf = None
         except Exception as e:
-            log.warning("Failed to load pixbuf from path: {}. Deleting file.".format(path))
+            log.warning("Failed to load pixbuf from path: %s. Deleting file.", path)
             log.debug(e)
             os.remove(path)
             return None
diff --git a/cozy/control/db.py b/cozy/control/db.py
index 935c7168..247dc618 100644
--- a/cozy/control/db.py
+++ b/cozy/control/db.py
@@ -25,7 +25,7 @@ def init_db():
     _connect_db(_db)
 
     sqlite_version = ".".join([str(num) for num in _db.server_version])
-    log.info("SQLite version: {}".format(sqlite_version))
+    log.info("SQLite version: %s", sqlite_version)
 
     if Settings.table_exists():
         update_db()
diff --git a/cozy/control/db_updater.py b/cozy/control/db_updater.py
index bd973110..ec66d02c 100644
--- a/cozy/control/db_updater.py
+++ b/cozy/control/db_updater.py
@@ -136,7 +136,7 @@ def _update_db_9(db):
             file = next((f for f in files if f.path == path), None)
 
             if File.select().where(File.path == path).count() > 0:
-                log.info("Path already existing in db: {}".format(path))
+                log.info("Path already existing in db: %s", path)
                 file = File.select().where(File.path == path).get()
             elif not file:
                 file = File(path=path, modified=track.modified, id=file_id)
@@ -144,7 +144,7 @@ def _update_db_9(db):
                 file_id += 1
 
             if TrackToFile.select().join(Track).where(TrackToFile.track.id == track.id).count() > 0:
-                log.info("TrackToFile already existing in db: {}".format(path))
+                log.info("TrackToFile already existing in db: %s", path)
                 continue
 
             track_to_file = TrackToFile(track=track.id, file=file, start_at=0)
diff --git a/cozy/control/filesystem_monitor.py b/cozy/control/filesystem_monitor.py
index bc826f9c..cfdf7a1f 100644
--- a/cozy/control/filesystem_monitor.py
+++ b/cozy/control/filesystem_monitor.py
@@ -100,10 +100,10 @@ def is_external(self, directory: str) -> bool:
                 return False
 
             if path in directory and mount.can_unmount():
-                log.info("Storage location {} is external".format(directory))
+                log.info("Storage location %s is external", directory)
                 return True
 
-        log.info("Storage location {} is not external".format(directory))
+        log.info("Storage location %s is not external", directory)
         return False
 
     def __on_mount_added(self, monitor, mount):
diff --git a/cozy/control/mpris.py b/cozy/control/mpris.py
index 42e0746d..28cce9d3 100644
--- a/cozy/control/mpris.py
+++ b/cozy/control/mpris.py
@@ -106,17 +106,17 @@ def on_method_call(
             result = getattr(self, snake_method)(*args)
         except AttributeError:
             invocation.return_dbus_error(
-                "{}.Error.NotSupported".format(interface_name), "Unsupported property"
+                f"{interface_name}.Error.NotSupported", "Unsupported property"
             )
         except Exception as e:
             log.error(e)
             reporter.exception("mpris", e)
             reporter.error(
                 "mpris",
-                "MPRIS method call failed with method name: {}".format(method_name),
+                f"MPRIS method call failed with method name: {method_name}",
             )
             invocation.return_dbus_error(
-                "{}.Error.Failed".format(interface_name), "Internal exception occurred"
+                f"{interface_name}.Error.Failed", "Internal exception occurred"
             )
         else:
             # out_args is at least (signature1).
@@ -409,3 +409,4 @@ def _on_current_changed(self) -> None:
     def _on_status_changed(self, status: str) -> None:
         properties = {"PlaybackStatus": GLib.Variant("s", status)}
         self.properties_changed(self.MEDIA_PLAYER2_PLAYER_INTERFACE, properties, [])
+
diff --git a/cozy/media/files.py b/cozy/media/files.py
index f31efb69..c4d9092a 100644
--- a/cozy/media/files.py
+++ b/cozy/media/files.py
@@ -52,7 +52,7 @@ def _copy_all(self, sources, destination: str):
                 self._copy_file(path, file_copy_destination)
 
     def _copy_file(self, source_path: str, dest_path: str):
-        log.info("Copy file {} to {}".format(source_path, dest_path))
+        log.info("Copy file %s to %s", source_path, dest_path)
 
         source = Gio.File.new_for_path(source_path)
         destination = Gio.File.new_for_path(dest_path)
@@ -72,7 +72,7 @@ def _copy_file(self, source_path: str, dest_path: str):
             else:
                 reporter.exception("files", e)
 
-            log.error("Failed to copy file: {}".format(e))
+            log.error("Failed to copy file: %s", e)
         self._file_progess += 1
 
     def _copy_directory(self, path, destination):
diff --git a/cozy/media/gst_player.py b/cozy/media/gst_player.py
index 27396c40..75083a1a 100644
--- a/cozy/media/gst_player.py
+++ b/cozy/media/gst_player.py
@@ -94,12 +94,13 @@ def state(self) -> GstPlayerState:
             return GstPlayerState.STOPPED
 
         _, state, __ = self._player.get_state(Gst.CLOCK_TIME_NONE)
+        print(type(state))
         if state == Gst.State.PLAYING:
             return GstPlayerState.PLAYING
         elif state == Gst.State.PAUSED:
             return GstPlayerState.PAUSED
         else:
-            log.debug("GST player state was not playing or paused but {}.".format(state))
+            log.debug("GST player state was not playing or paused but %s", state)
             return GstPlayerState.STOPPED
 
     @property
@@ -268,7 +269,7 @@ def _on_gst_message(self, _, message: Gst.Message):
                 reporter.warning("gst_player", "gst: Resource not found. Stopping player.")
                 return
 
-            reporter.error("player", "{}: {}".format(error.code, error))
-            log.error("{}: {}".format(error.code, error))
+            reporter.error("player", f"{error.code}: {error}")
+            log.error(f"{error.code}: {error}")
             log.debug(debug_msg)
             self.emit_event("error", error)
diff --git a/cozy/media/importer.py b/cozy/media/importer.py
index d5429372..884c55e6 100644
--- a/cozy/media/importer.py
+++ b/cozy/media/importer.py
@@ -198,7 +198,7 @@ def _filter_unchanged_files(self, files: List[str]) -> List[str]:
                         yield file
                 except Exception as e:
                     log.debug(e)
-                    log.info("Could not get modified timestamp for file {}".format(file))
+                    log.info("Could not get modified timestamp for file %s", file)
                     continue
 
                 continue
diff --git a/cozy/media/media_detector.py b/cozy/media/media_detector.py
index c5f3fb19..cfb1a6d4 100644
--- a/cozy/media/media_detector.py
+++ b/cozy/media/media_detector.py
@@ -34,7 +34,7 @@ def get_media_data(self) -> MediaFile:
         try:
             discoverer_info: GstPbutils.DiscovererInfo = self.discoverer.discover_uri(self.uri)
         except Exception as e:
-            log.info("Skipping file because it couldn't be detected: {}".format(self.uri))
+            log.info("Skipping file because it couldn't be detected: %s", self.uri)
             raise AudioFileCouldNotBeDiscovered(self.uri)
 
         is_valid_audio_file = self._is_valid_audio_file(discoverer_info)
diff --git a/cozy/media/player.py b/cozy/media/player.py
index e018a4b0..472c5563 100644
--- a/cozy/media/player.py
+++ b/cozy/media/player.py
@@ -380,7 +380,7 @@ def _emit_tick(self):
             position_for_ui = self.position - self.loaded_chapter.start_position
             self.emit_event_main_thread("position", position_for_ui)
         except Exception as e:
-            log.warning("Could not emit position event: {}".format(e))
+            log.warning("Could not emit position event: %s", e)
 
     def _fadeout_playback(self):
         duration = self._app_settings.sleep_timer_fadeout_duration * 20
diff --git a/cozy/model/book.py b/cozy/model/book.py
index 9e4d5bc2..a5b62775 100644
--- a/cozy/model/book.py
+++ b/cozy/model/book.py
@@ -216,7 +216,7 @@ def _fetch_chapters(self):
             except TrackInconsistentData:
                 log.warning("Skipping inconsistent model")
             except Exception as e:
-                log.error("Could not create chapter object: {}".format(e))
+                log.error("Could not create chapter object: %s", e)
 
         for chapter in self._chapters:
             chapter.add_listener(self._on_chapter_event)
diff --git a/cozy/model/database_importer.py b/cozy/model/database_importer.py
index 8629b14d..29aa10d8 100644
--- a/cozy/model/database_importer.py
+++ b/cozy/model/database_importer.py
@@ -81,7 +81,7 @@ def _prepare_track_db_objects(self, media_files: Set[MediaFile]) -> Set[TrackIns
             book = next((book for book in book_db_objects if is_same_book(book.name, media_file.book_name)), None)
             file_query = File.select().where(File.path == media_file.path)
             if not file_query.exists():
-                log.error("No file object with path present: {}".format(media_file.path))
+                log.error("No file object with path present: %s", media_file.path)
                 continue
 
             file = file_query.get()
diff --git a/cozy/model/track.py b/cozy/model/track.py
index 971be6b0..983fccbe 100644
--- a/cozy/model/track.py
+++ b/cozy/model/track.py
@@ -35,7 +35,7 @@ def name(self):
         if self._db_object.name:
             return self._db_object.name
 
-        return "{} {}".format(_("Chapter"), self.number)
+        return f"{_('Chapter')} {self.number}"
 
     @name.setter
     def name(self, new_name: str):
diff --git a/cozy/report/report_to_loki.py b/cozy/report/report_to_loki.py
index 6b779065..6720a100 100644
--- a/cozy/report/report_to_loki.py
+++ b/cozy/report/report_to_loki.py
@@ -61,7 +61,7 @@ def report(component: str, type: LogLevel, message: str, exception: Exception):
         labels = __append_label(labels, "distro_version", distro.version())
         labels = __append_label(labels, "desktop_environment", os.environ.get('DESKTOP_SESSION'))
 
-    line = "[{}] {}".format(LOG_LEVEL_MAP[type], message)
+    line = f"[{LOG_LEVEL_MAP[type]}] {message}"
 
     headers = {
         'Content-type': 'application/json'
diff --git a/cozy/view_model/library_view_model.py b/cozy/view_model/library_view_model.py
index 71079633..05eb56b2 100644
--- a/cozy/view_model/library_view_model.py
+++ b/cozy/view_model/library_view_model.py
@@ -240,11 +240,11 @@ def delete_book_files(self, book: Book):
             try:
                 os.remove(chapter.file)
             except Exception as e:
-                log.error("Failed to delete file: {}".format(chapter.file))
+                log.error("Failed to delete file: %s", chapter.file)
                 log.debug(e)
                 reporter.warning("library_view_model", "Failed to delete a file.")
             else:
-                log.info("Deleted file: {}".format(chapter.file))
+                log.info("Deleted file: %s", chapter.file)
 
     def play_book(self, book: Book):
         self._player.play_pause_book(book)
diff --git a/cozy/view_model/settings_view_model.py b/cozy/view_model/settings_view_model.py
index 28251f8a..716aa524 100644
--- a/cozy/view_model/settings_view_model.py
+++ b/cozy/view_model/settings_view_model.py
@@ -62,7 +62,7 @@ def add_storage_location(self):
 
     def remove_storage_location(self, model: Storage):
         if model.default:
-            log.error("deleting the default storage location {} is not possible".format(model.path))
+            log.error("deleting the default storage location %s is not possible", model.path)
             reporter.error("settings_view_model", "deleting the default storage location is not possible")
             return