@Dinoo: At "Le Lagon Bleue" you have the there well known "Menu de la Mer" and very good not expensive oysters.
For those whose is interested: The nude beach is about 2km and ends at the normal clothed/textile beach at Marseillan Plage. The special part for swingers, lurkers etc. is only a few hunderd meters and between the nude beach near the camping and the normal beach near Marseillan plage. I would say that it starts about 30-60m in the direction of Marseillan plage from the end of the camping and the 'poste de secours' (baywatch) which is located there.