Only 3 days after the film's release In the US, it was aired on television.
This movie wasn't released in the USA until 1974, over three years after it was made. The film was shot in France in 1970 and first released around the world there on 18 December 1970.
The car that Charles Bronson and Jill Ireland drive in to get a doctor was a red Opel Commodore GS/E I6.
This movie was cut by the British Board of Film Classification upon initial theatrical release in order for it to get a UK 'A' [PG] certificate. What was cut includes the sound of a neck breaking, a brief scene of topless nudity, and the shooting of a man with a flare gun. The movie then was later reissued with a UK 15 or AA certificate with the cuts restored.