Cheap holidays in france for family with two youngish boys , any ideas?

Must be near beach.
Answer
We went to prairies de la mer campsite in port grimaud near st. tropez. got a nice three bedroom caravan/lodge. went by coach because we went last minute and could not get cheap flights. £450 for 2 adults + 2 teenage child s. great deal, nice site right on the beach. nice entertainment at night too.