Hélène, a young waitress working in a bar frequented by German soldiers, saves the life of Pierre, a Resistance fighter. Her jealous lover has her arrested first and then released. Later on, Hélène is wounded while walking in the streets. Pierre has her transported to friends with the hope of taking her to London with him. Unfortunately, owing to lack of space in the plane, Pierre has to fly alone. Hélène has to wait several weeks before being able to board a new plane. When the day comes at last, the Germans are waiting for the plane on the clandestine airfield.

Four young friends share the carefree, cheerfulness, laughter and dances of Bohemian life. Rodolphe the painter, Alexandre Chaunard the composer, Colline the philosopher, as well as Marcel and his friend Musette. Mimi, a romantic young girl, falls in love with Rodolphe.

Paris, 1830. Fleur de Marie is rescued from poverty by the mysterious Rodolphe, who is in fact the Grand Duke of Gérolstein, who has gone incognito in search of an illegitimate child he once had. Which is not at all to the taste of Sarah Mac Gregor, her current mistress who kidnaps Fleur and has her locked up in Saint-Lazare prison.

The tailors Moïse and Salomon Lévy decide to marry Mina, Salomon's daughter to a good match, to save themselves from the competition that Cohen makes for them. Mina will eventually succeed in marrying Pierre, from a marriage of love, without this harming the family business.