Here is a french language file for Traq v3.5 (3.5.1). I think I am now up-to-date with the translations
To install this translation, download and extract the Zip file then upload the file 'frfr.php' in your vendor/traq/locale directory.
Feedbacks are welcome.
Edit for Jack: I have opened a new thread for each branch of Traq, as I can't either change topic title or add tags to an old topic. Please let me know if you feel it is more appropriate to you to keep a single topic by language.