Les diaboliques is an unusually intense movie. I believe this is due to the well thought out choice of real locations and the masterful use of spatial entities and textures. Your memory really gets hooked on those things, and it gives the story a sense of reality that makes you feel uneasy.
Les diaboliques is as much a horror movie as it is a thriller. When I watch this I perceive an intense mouldy smell throughout. The crumbling boarding school where the main characters live and act is worse than any nightmare even the swimming pool filled with murky water appears like a menacing abyss. The stifling crummyness is accentuated by the plot: School teachers sit at the sadistic principal's table in the refectory and have to force unspeakably ghastly meals down their throats (only one glass of wine is allowed). The second location is the principal's lover's apartment in a dead borough somewhere in no man's land. It's stuffy and utterly claustrophobic. The transfer between the two places is made with a "deux chevaux" station wagon its characteristic back part of corrugated sheet metal once was a common feature in our parts of the world, as was the snarling sound of the deux chevauxs engine. In the corrugated iron "box" sits a creaky wicker crate, which on the way back from the lover's apartment contains evidence of the crime, wrapped in a checkered wax tablecloth. So you see shells within shells, not unlike one of those Russian wooden dolls. You don't know what you will find in the innermost until the end.
