Justin, a lyricist by trade, and his friend Pierre, a composer, lead a bohemian life in Paris. Justin thinks his mother Josefa is richer than she appears, and decides to swindle her out of three million centimes by using Pierre as an intermediary in a case involving an insolvent check. Josefa uncovers the ruse and refuses to help her son. However, Pierre has discovered the identity of his friend's father, who had been unknown to him for twenty years. With the help of Justin's mother, the two friends do everything they can to extort the son's missing three million centimes from his ashamed and repentant father.

Fredo, a former gangster nicknamed "The Bluffer", has just been released from prison and is now thinking of going into the legal world with a friend. But his ex-partners are desperate to find him, to punish him for operating without their cooperation. His fortune is stolen and he is accused of a diamond robbery perpetrated by the old gang.

A young Italian is commissioned by the National Statistics Office in his country to carry out a social survey in France, in a large clothing establishment.

Three young students, who met on the train, arrive in Paris and decide to find accommodation together.

A robbery of 10 billion is successfully carried out by a Corsican gang led by a man called Toussaint. The heist is also the start of a war with a rival gang.