markkal is correct, may be it has changed with EASA.
As far as I know, you'll need to go through a lot of paperwork and at some point, if you manage to get that far, you'll have to pas an FI test as per JAR-FCL initial FI test with an examiner designated by the French DGAC.
That is how it was when I went through the process, and believe me, none of it was easy or fast, took almost a year.
Hopefully it is easier now with EASA regs. which are supposed to be law rather than an agreement to apply common rules that were JAR-FCL.
Paid positions are uncommon for FI's, under 200 in the whole country last I heard (talking about FI's for SEP PPL training).
Aero clubs are non profit organisations with few or no paid staff, and most of the FI's are "benevoles" (French for non paid volunteers).
Some of them do have some sort of arrangement to cover transport expenses for the FI's so that at least it does not cost them money to volunteer, as far as I know is not an official or regulated arrangement.
Aero clubs in France have been quite successful in the past decades and make flying at PPL level affordable for the vast majority, I wish every country in EU had this type of aero clubs in such big numbers (last time I looked there were 600 or so in France, and several hundred uncontrolled airfields were they operate from), really a rich aeronautical network.
They also had/have a strong federation grouping them, lobbying for their interests, with many members.
They have/had agreements in place with the different administrations that have helped them.
I believe that in the past few years the situation is not as good as it has been traditionally regarding those arrangements, also EASA coming in to force caused them some headaches.
I hope they keep on doing well in the future, in my humble opinion they do a really good job in keeping GA alive and widening the spectrum of people who can afford to fly at PPL level.
Good luck with your quest.
Last edited by LEVC; 11th Jul 2016 at 10:29.
Reason: Mistake