Don't know about France sorry but took a 6 & a 3 yr old to het heijdebos CP in the Netherlands and they both loved it. It had a second dome that was as big as the swimming dome that had a giant tropical-themed 'soft' play set ip within it - except it wasn't soft, it ws full sized with rope bridges, wooden climbing stuff, caves, streams, tropical plants, tropical birds and even some tropical animals (not many, in cages, all supported by WWF). It was great fun for kids and parents - dc absolutely adored it and would love to go back.
I think another parc - maybe one in Belgium - had a similar dome / adventure centre but pirate themed rather than jungle (so birds/animals replaced by pirate ship to scamper over but otherwise pretty similar) that I was contemplating as it was a little closer.
We went last week in august / early sept as there was a late bank holiday - Dutch schools had gone back a week earlier than us so was a step cheaper than the rest of the holidays!