Since you are not going until next season, time for some gentle research. Internet is obviously first choice but don't forget public libraries.
So much depends on personal preference and requirements that it's difficult to be more specific.
Some people like beach areas, some mountains,. Some to be near cities, some want the quietest countryside they can find. some want to folllow a historical interest (eg WW1) or see all the cathedrals
Some want sites with all the facilites, bars, entertainment, other prefer simple farm sites using the shower and toilet facilities of their own caravan.
Suggest you consider these sort of factors and see what you come up with. What ever the list you will find it in France somewhere.
On the practical side a few don'ts. Don't get too ambitious about travelling large distances. Don't make you plans too rigid - be prepared to change on the spot and stay longer or go sooner. There is not much advantage in booking out and back ferries on some routes (on the short routes it may be worthwhile) so if you have time you can keep your return dates a bit flexible and certainly the return route.
Consider using the toll autoroutes if you are uncertain about driving - you will find them much easier on the nerves until you get used to being on the'wrong side' Except in high season it is very rarely necessary to book campsites ahead unless you have a specific reason for being in a specific place at a particular time.
Browse through previous posting under the Overseas heading and there is a wealth of advice and comment available.
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