In a television interview ("Vivement Dimanche Prochain", France 2, 17 April 2005) Brigitte Fossey, who played the little Paulette, revealed that the film had originally been shot as a short, and then it was later decided to extend it into a feature film. Unfortunately she had lost her milk teeth and Georges Poujouly (who plays the boy Michel) had had his hair cut to play in Nous sommes tous des assassins (1952). So, in many scenes of the movie Paulette has false teeth and Michel is wearing a wig.
Brigitte Fossey claimed that when her family saw a newspaper ad searching for a 9 to 11 year old girl for a film, they brought her to the audition despite the fact she was only 6. She was then noticed by René Clément's wife and the major part of Paulette went to her.