Two cruisers, the Philadelphia and Augusta, provided gunfire support for French Army troops on the western outskirts of Toulon. Four days later these ships sent landing parties ashore, which included their Marine detachments, to accept the surrender of German forces on the is lands of Pomegues, Chateau d'If, and Ratonneau in the Bay of Marseilles. Some 730 Germans were taken prisoner in these operations. Overlord and Dragoon were the two main operations in the invasion of Europe in which the U.S. Navy played a leading part.
Quoted from A Different War: Marines in Europe and North Africa.
schrisbpd, perhaps the story you have heard is a deformation of that.