A horrific and, on the face of it, incomprehensible murder has just been committed on the unsympathetic person of a loan shark. The victim's body is found lifeless, but the circumstances of his death are far from clear. For want of anything better to go on, the police immediately suspect a penniless gentleman who had the bad idea and misfortune to be present at the time of the crime. The police don't take the time to look for other possible suspects, and are not at the end of their surprises. A dark story seems to lie behind this imbroglio of incoherent facts.

Philippe, an employee at the Bourdinet firm, having been caught kissing Jacqueline, his boss's daughter, is fired. Some time later, Bourdinet launches a radio quiz show to boost his business. Philippe then decides to compete in the hope of telling the thousands of listeners what he thinks of the industrialist. A blow on the head having given him a gift of second sight, the competitor becomes impeccable and wins astronomical sums to the great despair of Bourdinet. Everything will work out in the end and Philippe will be able to marry Jacqueline.

Father Benoît would like one of his twins to take over his inn, at 3 plates. But his ancillary ambitions are not commensurate with his last 3. Bernard is also in love with Hélène, daughter of Colonel Flouc de La Donzelle. He dreams of becoming an actor and goes to Paris to find a job. Difficult beginnings since from the theater, he goes to the cabaret, then to the radio, without success. In the final scene, the 3 brothers meet, which gives rise to a series of gags during the wedding.

A rich young man, Pierre Trévoux, has a desire for adventure and boasts of his courage. While he is staying with friends in the countryside, his hosts, to play a trick on him, organize a fake burglary, but he discovers the hoax. When he returns home, he finds his house broken into. Convinced that the game continues, he does not understand that he is dealing with real gangsters. His recklessness allows him to rout the criminals.

A banker threatened by gangsters is replaced by a tramp who is his perfect double. The gangsters arrest the fake banker and take him for a madman.

A freedom-loving man has found a way in the midst of loan sharks and apaches to get it almost totally with a minimum of work, needs and connections. After a few misadventures, he continues to wander in Paris whose streets he loves more than anything in the world.