Hello everyone,
Well my question is about as to whether the French version of Revit that I am using, is causing a conflict with the software API.
This conclusion had been deducted from some issues had with basic built-in nodes and custom nodes from famous packages.
Thank you for the effort you are making for the community.
The API is consistent, but if you are calling out built in parameters by name it can cause issues. Use parameter ID instead to avoid the issue.
The only localization-related issue I am currently aware of is that anything related to TextNotes will only work in the English UI. And, of course, what @jacob.small wrote.
If a comment solved your problem please mark it as solution (and maybe leave a like here and there).