Lac de Carcans-Hourtin This is the largest natural freshwater lake in France with 6000 ha. The lake of Carcans-Hourtin offers a 2km long beach in Maubuisson, a protected eastern bank and small beaches hidden in the conches to the west. Bordered by the dune and the forest, its environmental quality gives the lake a wealth of heritage and protected species. On foot, by bike, by boat ... come and discover this haven of peace.