Thank you for your post.
When you install FileMaker Pro, an Extensions folder is created inside the FileMaker Pro folder. Inside the Extensions folder should include "Labels" and "Labels (Inactive) " folders. If you are running the French operating system, then the "LabelsFrench.flb" file should be present inside the "Labels" folder. If not, then move the "LabelsFrench.flb" file from the "Labels (Inactive) " folder to the "Labels" folder, and the move the other .flb file into the "Labels (Inactive) " folder.
Relaunch FileMaker Pro, go into Layout Mode, and try to create a new Label layout.