Unless you go for an international (boarding) school where English is the or one of the vehicular languages, what you get is what is locally available: private schools which cost very little because the difference between them and your local state school is essentially that they are Catholic, ie there is religion in school, otherwise the curriculum is the same and the teachers are paid by the state; or your local collège or lycée de secteur.
There is a little flexibility in which school you go to depending eg on which first language you choose, your options for the Bac, that sort of thing.
FLE (French as a foreign language) is available only for primo-arrivants ie people who have just arrived in France and only for their first year IF IT IS AVAILABLE AT ALL. There are not enough FLE qualified teachers and they tend to be in cities where non-francophone children can be in a group which satisfies the accountants.
I cannot stress too highly just how sink-or-swim the system is.
Incidentally, you haven’t said what your son’s educational ambitions are, it would help if you did as I’d be able to give you less general information.
Where exactly is your house? I can tell you what your collège or lycée de secteur are, heads’ names etc so you can contact them, if you let me know. Also your son’s date of birth because the school year you go into is based on calendar year not academic year unlike the UK.