El profesional

Ennio Morricone's musical theme "Chi Mai" was composed for Maddalena (1971). The song was completely re-recorded in 1978 for the single "Disco '78" with heavier drums and in a different key. After hearing this version on the radio, Jean-Paul Belmondo was so impressed that he suggested it should be put into the soundtrack of his film. Ultimately, the record of this musical score was not only more successful than its initial release but came to be one of Morricone's bestselling work. The music was used again in the 80s for a Royal Canin commercial (a dog food brand) featuring slow-motion running dogs, and this became so famous that most people now associate "Chi Mai" with the commercial. It was even spoofed in Astérix & Obélix : Mission Cléopâtre (2002). When a national tribute for Belmondo was held right after his death in 2021 in the Hôtel des Invalides, "Chi Mai" was played.

When the tramps reach the car with the policemen inside, one of the tramps destroys a bottle on the roof of the car, so the roof gets wet and there are lots of glass splinters on it. In various shots afterward, the roof is completely clean.

Featured in Final Cut: Ladies and Gentlemen (2012)