I hope that this will prove helpful -
http://www.maladiecoeliaque.com/rsgacheter2.htm - which is a website listing things that you can buy in France that are gluten-free.
My sole fear is how much of the French you can understand. Basically it provides a list of producers of gluten-free foods - (
producteurs/fabricants) and you can access each company's website giving details of what products to look for. There is also a further list which shows where these can be bought.
General suggestions are that you look in '
bio' shops -biological products/wholefoods - and chemists. SOME bakeries offer 'pain sans gluten' especially individuals who are not part of a chain eg Banette.
They do remind you tactfully that beer is sometimes used as a raising agent, especially in the speciality
pain àla bière. Gluten-free foods are gaining ground in France, but ever so slowly.
I sincerely hope that you find good 'local' gluten-free food and that everyone has a wonderful holiday. Please do not hesitate to contact me if I can find out any special information for you.
I have looked at several of the websites given and if you can handle the French, and feel comfy about doing so, you could order products on line and have them sent to your address at the campsite ... some offer a Colissimo service for 8€ extra which is a French postal service offering a package guaranteed to arrive next day ......... so you could ask someone locally to help you with an order using the internet once you arrive at the site, but you will have to have a bit of help to fill in the items you require and make sure that the sending address - the campsite - is different from your billing address - where your credit card is registered.
If you think you will be going down this route, please remember to tell your credit card issuer that you are away from date x to date y so they won't stop your card because it's showing a different spending pattern ..............