Sweet Ecstasy (1962)

Original title: Douce violence

Olivier, a handsome but callow and moody young student, picks up an enthusiastic actress during a theatre rehearsal, and is introduced to her acquaintances -- a group of jaded rich kids who spend their time storming around the Riviera harassing passersby, throwing wild parties and following all the latest trends. When sexy Elke gives him the eye, he leaves the actress in the lurch and joins the gang for a decadent party aboard a yacht. However, Elke's wanton ways and Olivier's inexperience do not mesh, and in a snit, he accidentally sets the yacht afire. The gang wreaks its vengeance by luring him into a dangerous contest of bravura on a construction site.