Mauvaise Graine

Mauvaise Graine
Promotional release poster
Directed by	Billy Wilder Alexander Esway
Produced by	Edouard Corniglion-Molonier Georges Bernier
Written by	Billy Wilder Jan Lustig () Max Colpet Claude-André Puget
Starring	Danielle Darrieux
Music by	Franz Waxman Allan Gray
Cinematography	Paul Cotteret Maurice Delattre
Edited by	Therese Sautereau
Production company	Compagnie Nouvelle Commerciale
Distributed by	Pathé Consortium Cinéma
Release date	1934
Running time	86 minutes
Country	France
Language	French

Mauvaise Graine (English: Bad Seed) is a 1934 French drama film directed by Billy Wilder (credited as Billie Wilder) and Alexander Esway. The screenplay by Wilder, Jan Lustig (), Max Colpet, and Claude-André Puget focuses on a wealthy young playboy who becomes involved with a gang of car thieves.

Although Wilder and Esway shared the directing credit, in later years leading lady Danielle Darrieux recalled Esway was involved with the project in some capacity but clearly remembered she never saw him on the set. In her opinion the film, which marked Wilder's directorial debut, was his alone.

Set in 1930s Paris, the story centers on Henri Pasquier, whose wealthy father announces he no longer will support his playboy lifestyle. Dr. Pasquier sells his son's beloved Buick roadster, which Henri later sees parked on a street with the keys left in the ignition by the new owner. Unable to resist temptation, he takes the car to keep a date with a young lady he recently has met.

Henri is followed by three men who overtake him and bring him to the service station that serves as the front for a gang of car thieves. Believing he is one of them, they warn him not to compete with their operation. At the garage, Henri is introduced to the childlike Jean-la-Cravate, who invites him to stay at his flat with him and his sister Jeannette, who lures men away from their expensive cars so her brother's fellow henchmen can steal them. Jean convinces Henri to join his gang, and he and Jeannette soon are engaging in a series of daring thefts. When they manage to steal three luxury Hispano-Suizas, Henri insists everyone is entitled to better compensation, and the gang leader grudgingly agrees.

Perceiving Henri and Jeannette to be troublemakers, the leader sends them to Marseilles in a car with a damaged front axle, hoping it will crack and crash, killing the two. It does crash, but the couple escape without injury. They decide to sail to Casablanca and begin a new life, but Jeannette refuses to leave without her brother. Henri returns to Paris to retrieve him, only to arrive at the garage in the middle of a raid. Jean is shot and seriously injured, and Henri brings him to his father for medical treatment, but he dies. Dr. Pasquier, anxious to help his son escape a life of crime, gives him money so Henri and Jeannette can sail off and start anew.