Editing Les Diaboliques (film) (section)

===Casting===
Clouzot cast [[Simone Signoret]] in the role of Nicole. He previously filmed her husband [[Yves Montand]] in ''[[The Wages of Fear]]'', and the two couples became friends. The director was also aware of Vera's limitations as an actress and needed someone to lend her support in such a demanding role. Signoret signed an eight-week contract but the shooting actually took 16 weeks. She ended up being paid for only eight weeks of work despite staying until the end of the filming because she neglected to read the small print.{{sfn|Hayward|2005|p=16}} Signoret's co-star Paul Meurisse also recalls in his memoirs that the actress was further bemused by Clouzot's constant attempts to find clever ways of lighting Vera's face while muting the light on Signoret so she wouldn't upstage his wife.<ref>{{Cite book|title=Les éperons de la liberté|last=Meurisse|first=Paul|date=1979|publisher=R. Laffont|isbn=2221002644|location=Paris|oclc=5618616}}</ref>

Clouzot knew [[Paul Meurisse]] back from 1939 when the latter was trying to pursue a singing career. Clouzot then was trying to sell his song lyrics to [[Édith Piaf|Edith Piaf]], Meurisse's lover at the time. By the late 1940s Meurisse had become an established stage and screen actor, known for the roles of icy and sophisticated villains, and he seemed a natural choice for the role of Michel.{{sfn|Hayward|2005|pp=17–18}}

The film featured two Clouzot regulars: [[Pierre Larquey]] as M. Drain and [[Noël Roquevert]] as M. Herboux. [[Michel Serrault]] made his screen debut as M. Raymond, one of the schoolteachers. [[Charles Vanel]]—who previously co-starred in Clouzot's ''The Wages of Fear''—was cast as the seemingly inept Inspector Fichet.

Clouzot also auditioned 300 children and selected 35. Among them were Jean-Philippe Smet (the future [[Johnny Hallyday]]), [[Patrick Dewaere]]'s brother Yves-Marie Maurin, and [[Georges Poujouly]], who previously received acclaim in [[René Clément]]'s ''[[Forbidden Games]]''.{{sfn|Hayward|2005|p=19}}