hi
no pb for the French with NWC if you choose it, I send you a tuto with the translations of the commands, the rest is so intuitive that it won't be complicated.
Otherwise you can try MuseScore which is free and in French, knowing that the best first writing software is the one you'll use the most ;) and that once you're used to it, once your needs are well defined, adopting another software is as easy as changing your instrument when you master reading ;) (it will whisper in the halls)
friends
JJ