Michel (Martin Lasalle) goes to a horse race and steals some money from a spectator. He leaves the racetrack confident he was not caught when he's suddenly arrested. The inspector (Jean Pélégri) releases Michel because the evidence is not strong enough; Michel says it's not a crime to have cash.
Visiting his mother, Michel meets Jeanne (Marika Green) who begs him to visit his mother more often. Jacques goes on a date with Jeanne and invites Michel along. But after stealing a watch, Michel leaves Jacques and Jeanne at the carnival. While in a bar the inspector asks Michel to show him a book by George Barrington about pickpocketing at the station on a convenient morning, and Michel goes down to the police station with it. Once there, the inspector barely glances at the book. Michel goes back to his apartment realizing that it was all just a ruse to search his apartment. However, the cops failed to find his stash of money.
Michel's mother dies, and he goes to the funeral with Jeanne. Later, the inspector visits Michel in his apartment, and tells him that his mother had had some money stolen, but later dropped the charges, probably figuring it was her son who stole the money. The inspector then just leaves, and Michel decides to leave the country.
Returning to France, Michel goes back to steal at the horse track, where he is caught redhanded by the police. Jeanne goes to visit him in jail.