The screenplay is based on the 1937 Lemmy Caution thriller Poison Ivy by Peter Cheyney, which had been in 1945 the first title published in Marcel Duhamel's Série noire.

The story involves FBI agent Caution investigating gold smuggling activity in Casablanca.

[1] Considered either "tongue-in-cheek"[2] or "doddery",[3] the film "utilizes all the rules of the genre, albeit without convictions: chases, fistfights, nightclubs, unusual settings, knowing winks at the public".

[4] It was a commercial success in France (3,846,158 French entries in 1953) and was followed by 7 other Lemmy Caution films until 1967, not counting Jean-Luc Godard's "incomprehensible"[5] Alphaville, a strange adventure of Lemmy Caution,[6] casting Constantine and Vernon.

This film was considered "emblematic of French postwar attitudes towards the United States: a fascination for U.S. culture tempered by fear of U.S.