The roles of Jean Diego and Malou were originally to be played by then-lovers Jean Gabin and Marlene Dietrich, who had recently returned to France after the end of the war. Dietrich pulled out of the project at the last minute, however, and Gabin followed her. With the rest of the cast already selected and production scheduled to begin soon, Carné and Prévert had to choose an unknown actor for the role of Jean Diego, a singer/performer who had recently had some success in the French Music Halls - Yves Montand.
Edith Piaf personally - and persistently - lobbied Marcel Carné to choose her then-lover Yves Montand for the role of Jean Diego.
Brigitte Auber's debut.
As the leading roles were to be stars like Jean Gabin and Marlene Dietrich, it seemed very difficult to film on location in Paris the scenes involving the subway station of Barbés Rochechouart . The producers decided to build a complete duplicate of this station on the outside stage of Joinville studios..