Diabolique (1954)

Les Diaboliques (French: [le djabɔlik], released as Diabolique in the United States and variously translated as The Devils or The Fiends) is a 1955 French psychological horror thriller film co-written and directed by Henri-Georges Clouzot, and starring Simone Signoret, Véra Clouzot, Paul Meurisse, and Charles Vanel. The story blends elements of thriller and horror, with the plot focusing on a woman and her husband's mistress who conspire to murder the man. It is based on the 1952 novel Celle qui n'était plus (lit. transl. The One Who Was No More) by Pierre Boileau and Thomas Narcejac.

Clouzot, after finishing The Wages of Fear (1953), optioned the screenplay rights to the novel, preventing Alfred Hitchcock from making the film. The film helped inspire Hitchcock's Psycho (1960). Robert Bloch, the author of the novel Psycho, stated in an interview that his all-time favorite horror film was Les Diaboliques.

Released in France in January 1955, Les Diaboliques was the seventh highest-grossing film of the year, with a total of 3,674,380 admissions. It received largely favorable reviews from French critics, and won two Louis Delluc Prizes (for Best Film and Best Performance by Signoret). While reception in the United Kingdom was mixed, the film was favorably received by critics in the United States, where it won the title of Best Foreign Film of the year by the New York Film Critics Circle and the National Board of Review. By late 1956, it had become the highest-grossing French film released in the United States at that time.

Les Diaboliques went on to garner a reputation as a classic film with significant influence on the horror genre, particularly due to its twist ending.