Yogi's right, the standard joining proceedure in France is a 45 degree join to downwind at circuit hieght, reporting joining downwind and then at downwind. But I have requested overhead joins/straight in approaches etc. in the past and this has been OK, as I said before, dont be afraid to ask, they are an obliging lot over here!
La Rochelle is a lovely town, nice airport. I also seem to remember that La Rochelle has a published joining proceedure though. If you want a less busy/relaxed, but English speaking airfield you could try nearby Royan, its got a nice little cafe too.
Regards, SD