Petrus, a Montmartre photographer, is accidentally wounded by Migo, a dancer at the Frou Frou night club, when she is trying to shoot her faithless lover Rodrigue, a counterfeiter. Though Petrus tries to reconcile the lovers, Migo lands up with him after Rodrigue is finally killed by another jealous dancer.

Employed in a beauty salon, Amédée must undergo a pentothal injection. The dose is too strong; suddenly Amédée reveals the truth to everyone; to clients of the institute; to his cheating wife; to his boss that he robs; to the tax collector; etc. When the effects of the truth serum wear off, everyone returns contentedly to their little swamp.

An art dealer in dire straits, after being ripped off by two crooks, one of whom owns a genuine painting by Gauguin while the other is an expert copyist, finds them again and, instead of killing them as he originally intended, joins in their game – with ultimately disastrous results.

The Raffin Commissioner investigates the murder of an industrialist and it soon becomes apparent that the activities of the relatives of the deceased all revolve around the Folies-Bergere.

A small-time thief steals a car and impulsively murders a motorcycle policeman. Wanted by the authorities, he attempts to persuade a girl to run away to Italy with him.

Struggling actor Simon witnesses a murder; he didn't see the killer, but that doesn't stop him from claiming that he did in order to get his name into the papers. Sure enough, the murderer targets him as his next victim. Our hero is temporarily rescued by Jeanne, a fellow aspiring actress who has always had a crush on him.

Vallois, a vice inspector for the Paris police, takes special interest in the plight of drug-addicted Lucky (Najda Tiller), whom he considers to be more victim than criminal. Taking it upon himself to wean Lucky away from narcotics, Vallois also wins her love -- and, incidentally, smashes the dope ring responsible for her addiction.