Trivia

Because no funding was available from any of the studios, François Truffaut and his crew shot the film on the fly on the streets of Paris, often making up the script as they went along. The ending was decided on the basis of who was available at the time of shooting.

The opening chase scene is so dark because the rain kept blowing the bulbs of the lights cinematographer Raoul Coutard was using to light the scene. Due to budgetary restrictions and the fact he was making a film noir, François Truffaut simply decided to continue shooting with minimal lighting, resulting in moments of almost total visual obscurity at points throughout the scene.

Although this was a hit with the critics, it bombed at the box office. Enough to make François Truffaut forgo his improvisational techniques and return to regular scripted drama.

The character of Charlie is partially based on François Truffaut himself. The director allegedly suffered from acute shyness, and there is a strong visual resemblance between Charles Aznavour and Truffaut.

As Charlie, Léna, and the two kidnappers are driving down the road, a truck in front of them bears a large "Cahiers du Cinéma" sign. Director François Truffaut wrote for "Cahiers" and dedicated The 400 Blows (1959) another of his films to its founder, André Bazin.