The brave Monsieur Breloque has a friend, Pierre Martel, a private detective. When the latter asks him to replace him for a while, Breloque, although having no competence in the matter, accepts. He anticipates adventures and misadventures but also happy surprises.
The film portrays the relationship between a female Moroccan student, who has been forced to leave her studies at the Sorbonne for financial reasons and works as a dancer in a Paris nightclub, and a French naval officer. However, on returning to Casablanca she is tricked into believing that he had the led attack on her village that wiped out her family. She begins to plot her revenge.
Serge loves living it up but painting the town red has a price... too high for him! What to do then? Alfred, his servant and former pickpocket, has the solution : steal of course! No sooner said than done ! Or rather: No sooner said than tried... For when Serge, assisted by his mistress Gloriane acting as bait, he tries to rob a jeweler on the Place Vendôme of a precious diamond bracelet, he realizes that a gang of thieves have preceded him. Later on, he will learn that the boss of the gang is a Polish noblewoman, Countess Waldapowska.
A renowned doctor and his brother live and work together until the brother falls in love with Marie, a singer, and gives up medicine to be with her. After a time however, she misses her old life and goes back on the stage - an act which leads her lover to commit suicide. Later the doctor and Marie also meet, and she becomes his mistress. He finds out about his brother's suicide and goes through his artifacts looking for a clue as to what might have been the cause. He finds a photograph of Marie and realizes the truth, which decimates their relationship.
A wealthy young businessman consecutively falls in love with a classy English woman (Pearl), a Russian sculptress (Athalia), and a naive working-class girl (Lucie).