It can depend on how old your son is and where in France you'll be located. There are pretty strict work rules that discourage kids from working until they are at least 18, and the school system doesn't really leave students much time for activities like bands.
There are, however, local music schools that offer lessons in everything from guitar to drums to harp or cello. Lessons are mostly on Wednesdays (when school isn't in session) and I've heard great things about these music schools.
Cheers,
Bev