Naive and good-hearted Léon Ménard arrives in Paris, determined to find work in the capital. In a café, he meets Bob, a seedy guy, who helps him to get a job. On cloud nine, the ingenuous young man, does is unaware of how Bob manipulates him. Having become the night concierge of a hotel, the thankful Léon lets Bob and his accomplices get into the pace. Jewels are stolen as a result.When he is accused, Leon refuses to incriminate his "friend". Fortunately, Charlotte, Léon's fiancé, manages to find evidence of Bob's guilt and thanks to a premium paid by the diamond dealer the two lovebirds can buy a grocer's shop and tie the knot.

Suspected of murder, a man disappears under mysterious conditions, which only increases the charges against him.

Summoned by his mother to plead, a very young lawyer has a trio of pathetic criminals acquitted. The daughter of one of them reveals to the lawyer that the three accomplices hoped to find food and board in prison. For the beautiful eyes of the young girl, Master of La Bastide attaches the three rogues to his service. Disasters, confusion, clumsiness follow one another until the planned wedding.

Micheline, who fled to Paris with the man she is in love with, finds herself on her own when he abandons her. She lands in a reformatory from which she manages to escape.

Miquette is a young woman whose beauty and vivacity increase the clientele of her mother's tobacco shop. A Barrymoresque actor believes that Miquette has star potential, but he hasn't sufficient capital to finance her theatrical debut. He manages to get the money by practicing a bit of genteel blackmail on an aging marquis who has romantic designs on the heroine.

Léon Ménard, a farmer and an apparently simple man of the country, is invited to visit his uncle Henri Ménard, a prosperous industrialist. He encounters a number of people scheming to marry into the Ménard family for the sake of money. Ménard discovers and thwart the plots and manages to unite a young couple who truly are in love. The romantic comedy ends happily with a double marriage. Henri's daughter Nicole marries Didier, and Ménard marries his new-found love Rosine. It turns out that Léon is "not so stupid" after all.