Gangsters from the United States try to kill a key government witness whose testimony could help land an influential mobster in jail. It's up to detective Maigret to deal with the FBI and a series of underworld figures to save the life of the witness...

• Les Films Copernic
• Titanus
• Jean Gabin
• Françoise Fabian
• Michel Constantin
• Paul Frankeur
• Guy Decomble
• Paulette Dubost
• Laurence Badie
• Marcel Bozzuffi