The third in a series of films featuring François Truffaut's alter-ego, Antoine Doinel, the story resumes with Antoine being discharged from military service. His sweetheart Christine's father lands Antoine a job as a security guard, which he promptly loses. Stumbling into a position assisting a private detective, Antoine falls for his employers' seductive wife, Fabienne, and finds that he must choose between the older woman and Christine.

Parisian everyman Antoine Doinel has married his sweetheart Christine Darbon, and the newlyweds have set up a cozy domestic life of selling flowers and giving violin lessons while Antoine fitfully works on his long-gestating novel. As Christine becomes pregnant with the couple's first child, Antoine finds himself enraptured with a young Japanese beauty. The complications change the course of their relationship forever.

Diego is one of the chiefs of the Spanish Communist Party. On his way from Madrid to Paris, he is arrested at the border for an ID check but manages to get free. When he arrives in Paris, he starts searching for one of his comrade to prevent him from going to Madrid where he could be arrested.

Professor Louis Delage is a kidney transplant specialist. He is so good in his field that his peers nickname him the "great man". But one day, one of his patients die during surgery and Delage starts doubting. Is he actually such a great man? To fight desperation he decides to take in the deceased child while devoting more time to Florence, his hitherto neglected wife.

Recovering from an attempted suicide, a man is selected to participate in a time travel experiment that has only been tested on mice. A malfunction in the experiment causes the man to experience moments from his past in a random order.

Two ambitious young provincials, Patrick and Michel, go to Paris to seek their fortune. Patrick seems to be the epitome of the up-and-comer at any price: with no scruples whatsoever, he manages to break into the world of finance, i.e. into the home of banker Philippe Haguenauer. He soon becomes the lover of the woman, Hélène, director of a major fashion house, while Philippe, for his part, is having the perfect love affair with Nadine, his secretary. And this with the mutual consent of both spouses. Meanwhile, Michel, shy and sentimental, is looking for a situation, while remaining honest.

Jacques Herbelin is the faithful husband of Louise and the proud father of Cécile, a kind little girl. But Louise does not reciprocate her husband's affection and prefers to cheat on him in the arms of Marquis de Condottier. The latter is a sinister character who, not satisfied with being Herbelin's wife's lover, sets his heart on their daughter, who has now become a pretty young lady. Jacques can't take it anymore.

The romantic life of the head of a bandit gang, wanted by the police. Cartouche gets away with being deported to Louisiana after unmasking a plot by a Duke against the throne.

Véronique Lanier runs one of the most highly rated haute couture houses in Paris. Her first partner is her husband Pierre, who has left aside a promising artist career to design the styles which make their firm a success. The trouble is that Véronique lives only for her job and does not allow herself -and her husband for that matter - a moment's respite. In Cannes, Pierre meets Wanda, a young singer with strange, fascinating eyes. The frustrated husband falls for her but gradually realizes that the light mercurial creature cannot possibly fulfill him. Véronique, feeling miserable, understands she is on the wrong track. She promises Pierre that she will make efforts to reconcile work and married life. Véronique and Pierre will live and work together again, each one forgiving the other for their faults.

A young man returns to the family home to face a childhood trauma: his brother's suicide, but nobody in the family is willing to help him.

Régine was married to Léon. She is currently engaged to Daniel, but still has feelings for Maurice. Young Georgette would like to find me a sister at any price, but her friend Magali would only commit herself for the right reason. Ferdinand is Léon's diligent valet. They all meet up at a winter sports resort. During a wild night, we witness the figures of a most successful quadrille.

A penniless adventurer, Eddie Morgan survives on his wits and good humor. He's a bluffer. To help the owner of an oil field, he launches a vast investment campaign, with the help of a few friends, to benefit the French people. A rival group, led by Serge Colonna and Dominique Ardan, tried to buy the land from him, because according to an expert, there was no oil to exploit. But the expert had lied, and Colonna had just signed the purchase contract. Eddie, with the help of Dominique, whom he has seduced in the meantime, snatches the famous paper from Colonna's hands. The oil can flow.

Mr Jo, nicknamed "the man with the Buick", is the darling of the small town of Honfleur. But he is in fact a trafficker with a bad reputation who would like to forget about his past, now limiting himself to smuggling rubies under the cover of a charitable organization which offers underprivileged children holidays in Switzerland. However, Mr. Jo is in love with a pretty widow and, in order to marry her, he is willing to get involved in a hold-up again. And "the man with the Buick", who seemed so honorable, will surprise the inhabitants of Honfleur when Inspector Menard reveals his secret activities.