We went two years ago to a Keycamp site in the south of France in early September and it was fine. Our boy was 3 and the majority of kids matched up to his age, he had a ball. It certainly wasn't empty!. The kid's club wasn't operating but the shop/bar and some entertainment were still available. The nice thing is that when you travel outside the camp, the local towns are more relaxed. Plus you get the whole Summer to look forward to your holiday!
We used to always o end Aug/beg Sept before kids started school - it is a but quieter but only site that closed down on us was in Northern Brittany! Further south the season lasts longer so you'll be fine.
Me, DH and DD (who will then be 21 months) are thinking about going on a eurocamp style holiday and we can't get time off work til the first week in sept. Prices dip right down then which is obv good but I don't want to stay in a ghost town!! Not too fussed about loads of entertainment but don't want to feel like we're the only ones there or find that the on-site shop/restaurant is closed and we're stuck!!
Anyone got any experience of going at that time of year??
Catalonia coast is our preference but would be up for te southern half of France too.