Before you can get on the air, you need to be licensed and know the rules to operate legally in France.
The ANFR website (in French, yes I know...) is your official source of information.
You can as well join a club, they are certainly a very handful source of information and some of them can prepare you to be licensed as well.
You can as also prepare yourself at home using online resources:
This online resource is very handful and has the advantage to be up-to-date thanks to F6GPX, F5AWG and F6GPX work.
Ham Radio online training courses - HAREC By ON7PC Pierre Cornélis
Superb Online training course if you are serious in getting licensed.
We warmly recommend you to have an in-depth look and make it your main source of training.
The course is fully aligned with the CEPT T/R 61 recommendations.
I strongly recommend you to read the introduction text before downloading the full technical course.
Comment sensibiliser les jeunes aux métiers de l’électronique et de la radio?
Nous vous proposons des animations gratuites d’une journée dans vos établissements soit pour les niveaux CM2 de l’école primaire soit pour les élèves des collèges et des lycées.
And to close the subject, the French Ham Radio technical reference book: