diff --git a/CODESTYLE.md b/CODESTYLE.md
index dcd23ff20..1ac729a8c 100644
--- a/CODESTYLE.md
+++ b/CODESTYLE.md
@@ -57,9 +57,13 @@ New files should be prefixed by the following license header, where `${current_y
 ```
 * use string interpolation (f-strings, https://peps.python.org/pep-0498/),
   rather than the string `format` method (https://podalirius.net/en/articles/python-format-string-vulnerabilities/)
+* prefix names of all private fields, methods and variables with underscore (_).
+  This allows any code maintainer to immediately spot which code elements can be freely modified
+  without having to worry about the external context.
+  Note: private elements are only called within the modules in which they are defined.
 
 ## Code
-The code should be pretty easy to apprehend. It's not perfect but it will improve over time.   
+The code should be pretty easy to apprehend. It's not perfect, but it will improve over time.
 Some documentation about development is available [here](https://docs.dfir-iris.org/development/).   
 Here are the main takes :