Bob Letellier, a good looking rich kid who studies science, makes the acquaintance of Alain, a cynical and immoral young man. The latter introduces him to the existentialist circles of Saint-Germain-des-Prés. Bob is invited to a party and becomes Clo's lover, a rich heiress.
| Actor | Role |
|---|---|
 Jacques CharrierRobert 'Bob' Letellier | Robert 'Bob' Letellier |
 Pascale PetitMic | Mic |
 Andréa ParisyClotilde de Vaudremont | Clotilde de Vaudremont |
 Laurent TerzieffAlain | Alain |
 Roland LesaffreRoger | Roger |
 Pierre BriceBernard | Bernard |
 Jean-Paul BelmondoLou | Lou |
 Dany SavalNicole | Nicole |
 Denise VernacLa mère de Mic | La mère de Mic |
 Jacques MarinHippolyte Félix | Hippolyte Félix |
 Jacques Perrinle jeune qui monte sur la Vespa | le jeune qui monte sur la Vespa |