schrieb:

I have found a few aeroclubs in the area which seem to be OK, but they
generally want a joining fee of 100+ Euros.

In Europe in general and in France in particular, most private flying is
done on a club basis. Hence to rent such a club plane, you must become a
member of the aeroclub. The reasons are such as taxes (the club looses
its tax privileges when it runs a commercial business such as renting to
non-members), but also insurance and the like. Usually the joining fee
is something like 100 Euros for a one year membership.

There are some commercial renters (mostly training facilities), but not
many. I second Silvain's advice to ask in the French aviation group, as
there tend to be some native French there.