Brothers Moïse and Salomon run a modest bazaar near the Butte Montmartre, under the sign of "everything for nothing". There are office items, perfumes and leather goods. Their niece, the beautiful Lia, twenty years old, a graduate in synthetic chemistry, lives under their roof. She is less close to her pennies than the old grigous, and willingly visits the store "Aux femmes françaises", administered by the very Christian Valois family, where she hopes to place products. of its creation; perfumes, make-up and ointments of all kinds.

The manager of a firm has a very unusual idea : asking his employees to pose as gangsters and to hold up a bank before returning the stolen money and pocketing the reward. But things do not go according to plan and the phony thieves get stolen in their turn. They have no other choice than turning into amateur detectives to be able to pay back the stolen dough.

Thanks to a bit of string-pulling by his aunt, Jean du Bois d'Ombelles, a young recruit who has blue blood in his veins, hopes to go through a nice and comfortable military service. Unfortunately he becomes Corporal Bourrache's pet aversion. Nevertheless, against all expectations, Jean ends up taking a liking for military life.

A young man in love with a married woman takes the husband's place in the barracks and finds his rival there. But the fact that there are two Champignols in the ranks gives rise to many misunderstandings. But the husband preferring his painting, willingly abandons his pretty wife to the lover.

A young intellectual, Hugo, joins the Communist Party out of a sense of idealism, only to see his principles manipulated by party leaders. He is given the assignment of killing Professor Hoederer, a party deviationist. However, he grows to admire the man and begins to have doubts about morals and revolutionary politics. But jealousy - Hugo thinks Hoederer has made love to his wife, Jessica - takes matters out of the political realm.

The former "J3" who used to be pupils at the Coutances high school are currently students in Paris. It is now a time for love stories and sentimental crises. For the moment all the boys'hearts beat for Anita, a princess, who is the splitting image of their philosophy teacher at Coutances, Mademoiselle Bravard.