Not quite France but a few years ago we went to one of the Dutch Centre Parcs - which are cheaper than the French ones (I think the Belgian ones are cheaper too). We also went for the last week around our Bank Holiday weekend - Dutch kids go back to school a week earlier than ours so it wasn't in Dutch peak time which also helped.
The one we went to was Het Heijderbos - we drove from Calais to Ypres, stayed overnight in the Novotel (right off the main square, got a great deal, didn't include breakfast but there's a bakery over the road so we bought way too much plenty of yummy stuff and ate in our rooms for about a fiver compared to expensive hotel breakfasts. Ypres is a lovely town to walk around (dc were about 3 and 6 at the time) - small enough to be walkable, a nice main square with plenty of history, plus all the WW history which they were able to appreciate a little (and have come back to as it's turned up in their syllabuses at school). Or you could do it in a 3.5 hour drive from Calais - but because of the distance we'd done before Calais already that day we wanted to have a break.
The CP was great - the favourite bit was the second dome they had that was as big as the swimming pool one but with what's probably described as a tropical jungle themed climbing/exploring/adventuring thing going on - caves, streams, tropical plants and animals, rope bridges, zip wires, treetop walks, sand, climbing stuff (adult sized rather than soft play kids stuff but kids could do pretty much all of it with a bit of adult help if needed). Just like you'd expect the jungle zone to be like on the Crystal maze! It's the only CP with that but there's one in Belgium that has something similar, think it's got a shipwrecked pirate theme. Have been eyeing it up - not least as it's closer than the dutch one!
I've never been to a CP here but there, there weren't any chain restaurants, it was all their own things. There were also plenty of smaller play parks for the younger ones, the pools were nice and there was a scuba area that looked good for the older ones (needed to be a confident swimmer for it). Of all the holidays that the dc have been on, that's the one that they would most like to repeat!
Best of all - despite being much further to drive to than a UK CP, involving a ferry crossing and two additional overnight stops at hotels to break the journey up - it was still significantly cheaper to go to Het Heijderbos than it was to go to a CP in the UK the same week.