It's a comedy-drama set in 1943 occupied Paris. Alain Delon is the 17-year old son who's making a lot of money with his partner, Jean-Claude Brialy, in black market dealing, mostly alluded to and not shown. His dad, Bourvil, has no idea what his son is up to. Delon's school grades fall off because he's taken up with Françoise Arnoul. Brialy's dad is Lino Ventura. Humorous complications arise when Bourvil investigates and meets Ventura, who runs a saloon and is in with loose women, one of whom he sets upon Bourvil. It's mostly good fun, without the occupation being taken too seriously. The two user reviews on IMDb accurately give you the drift.