La Rochelle
Just do some thorough flight planing / preflight study and you will be fine. Read carefully the information posted in the SIA, reporting points, etc. Flying in France is not difficult at all. Make sure you have zone and airport frequencies handy and the controllers will help you navigate your way. It is a very friendly GA place. All controllers speak english, and -unlike the UK- have radar. As long as you have a transponder equipped airplane, you will be just fine. Transit through controlled airspace is a lot less of a big deal like it is in the UK. French only airports are a bit more challenging, but all you need is to know how to report your position approaching and in the circuit and in and out of the runway, not more than 15 minutes of studying.
You will normally find convective weather in the summer. Simple way to minimize it is to plan early starts and not wait until is too hot (afternoon).
Enjoy it, and don't feel discouraged by negative comments!