During the shooting of this film, the director Jean-Pierre Melville had no respect for Charles Vanel and treated him badly on set. Actor Jean-Paul Belmondo got so mad at Melville that he slapped him on set.
Yves Boisset, who was assistant to Melville on the shooting, confessed that Melville asked him to find some local American extras for the bar fight. And one of them was a student named Robert De Niro, who was twenty years old at this time. But Melville rejected him.
In the New York City footage, shot circa October 1962, West Side Story is at the Rivoli, The Longest Day is at the Warner, and Mutiny on the Bounty is at the State; as the sequence ends, we also see The Chapman Report at the Criterion; theatre buffs will also see the Trans-Lux and the Forum.
As the plot is mainly about a flight throughout the United States from New York to New Orléans of the two main characters played by Jean Paul Belmondo and production could not film on locations; the indoor scenes were shot in Melvilles's own studio in Paris with the addition of many rear projections for the scenes inside cars.
This was the first color and widescreen film directed by Jean-Pierre Melville, as well as his only film in any sort of CinemaScope process.