Hi OP, sorry for being late to reply, hope it's still useful
I've been wearing hearing aids since age 7, and I bought my first pair in France about 2 years ago.
The process (assuming that you have a carte vitale and a mutuelle)
Go to your Dr and ask for two ordonnance. One is for an ORL hearing test and the other is for the hearing aids - this will entitle you to any government subsidy.
Go to an ORL and get a proper hearing test.
Go to several different audiologists - they really do vary. I had rdv and got devis from Audika (ok, but they really push their own brand of aids), Acuitis (opticians that have branched out into audiology) - I wasn't impressed by either the knowledge of the audiologist, or the range they offered. I ended up going with Audition Conseil - great service, wide range of hearing aids on offer.
You need to get a devis from the supplier. They should all be able to tell you how much the CPAM and mutuelle will reimburse, or you can research yourself. So you will know how much you have to pay yourself.
Once you have chosen, you'll likely have to send the devis, plus the ordonnance and the ORL results to your mutuelle and get that approved. Once you receive that, you go back to the audiologist. Some audiologists will do all this for you, others wont.
The price of hearing aids in France is gobsmacking. Admittedly I've gone for good digital aids (Starkey) but the cost break down for 2 aids was roughly...
Total Cost €4000 (€2000 each ear)
CPAM reimbursement €200 per ear = €400
Mutuelle (this will vary) €500 per ear = €1000
I paid €2600. Some audiologists will let you pay in installments.
HTH