''Les Diaboliques'' (''The Devils''), also known as ''Diabolique'', is a [[UsefulNotes/{{France}} French]] suspense-thriller made in 1955 and directed by Creator/HenriGeorgesClouzot, [[TheFilmOfTheBook adapted from]] the 1951 novel ''Celle qui n'était plus'' (''She Who Was No More'') by Creator/PierreBoileau and Creator/ThomasNarcejac.

Christina and Nicole, respectively the wife and [[TheMistress mistress]] of Michel the JerkAss boarding-school headmaster, conspire to kill him. However, after they carry it out, his body disappears, and then things just get weirder. Christina and Nicole are played by Creator/VeraClouzot and Creator/SimoneSignoret, while Creator/PaulMeurisse plays Michel.

Rumpled, folksy detective Fichet, played by Creator/CharlesVanel, was the inspiration for ''Series/{{Columbo}}''.

[[ForeignRemake Remade in the U.S.]] twice, first as the 1974 MadeForTVMovie ''Reflections of Murder'' (starring Creator/JoanHackett as the wife, Creator/TuesdayWeld as the mistress, and Creator/SamWaterston as the brutish husband) and then again as the 1996 theatrical film ''Diabolique'' (with Creator/IsabelleAdjani as the wife, Creator/SharonStone as the mistress, Creator/ChazzPalminteri as the husband, and Creator/KathyBates in a GenderFlip role as the police detective).

!!This movie contains examples of:

* AssholeVictim: Michel, with so much emphasis on "asshole" that the "victim" part almost fades in comparison. [[spoiler:Subverted eventually, as the ending reveals that he has been alive and working together with Nicole the whole time. Double subverted when Alfred Fichet catches them both and arrests them]].
* BoardingSchoolOfHorrors: L'institution Delassalle might not be quite as extreme as some examples, but it's still a run-down dump overseen by the sadistic headmaster Michel.
* CeilingBanger: Nicole's upstairs tenant, attempting to listen to a radio quiz show, is aggravated by her noisily filling her bathtub at 10 p.m.
* ChekhovsSkill: [[spoiler:Michel is referred to as a former champion swimmer, which allowed him to hold his breath long enough to make the drowning seem real.]]
* CutHimselfShaving: Nicole gives a lame excuse for a black eye that was apparently caused by Michel.
* DisposingOfABody: Or appearing to, anyway.
* DomesticAbuse: Michel is physically and emotionally abusive toward both Christina and Nicole.
* DoNotSpoilThisEnding: Translated from French, the final title card after the film reads:
-->Don't be diabolic yourselves! Don't ruin the interest your friends could take in this film. Don't tell them what you saw. On their behalf, we thank you.
%%* DrivingADesk
* EmptyPilesOfClothing: The women freak out when the suit Michel was drowned in [[spoiler:is returned to the school from a dry cleaners.]]
* TheEndingChangesEverything: [[spoiler:The whole movie is a plot by Michel and Nicole to kill Christina. She has a weak heart, which they use to frighten her to death.]]
* {{Fainting}}: Christina, after the swimming pool where Michel's body was dumped is drained empty... and the body is gone.
* FakingTheDead: [[spoiler:Michel wasn't dead at all. It was a trick to fool Christina.]]
* FocusGroupEnding: The remake completely changes (and arguably ruins) the ending. [[spoiler:Mia doesn't die, Nicole panics, and in the end Mia and Nicole drown Guy (the husband) in the pool, for real. The detective then helps them cover it up.]]
* {{Foreshadowing}}: Early scenes establish that 1) Christina has a lot of money of her own, and 2) she has a heart condition.
* FrightDeathTrap: [[spoiler:Christina, driven wild by fright, has her fatal heart attack after Michel rises from the tub.]]
* {{Gaslighting}}: [[spoiler:Nicole and Michel are plotting to drive Christina mad with fear.]]
* GenderFlip: Kathy Bates as the Fichet-{{Expy}} in the 1996 remake.
* HollywoodHeartAttack: Averted. [[spoiler:The fatal heart attack at the end is ''disturbingly'' realistic]].
* HomoeroticSubtext: The film implies that Christina and Nicole are lovers -- one scene shows them in the same room in pajamas, and later they speak of running away together. This is never expressly portrayed or stated, however; there were some things you just couldn't do in 1955, even in France.
* KnowNothingKnowItAll: One of the teachers, M. Raymond, comes across as this.
* MaybeMagicMaybeMundane: In the last scene, a kid claims to [[spoiler:have talked to Christina, who died from a heart attack earlier]]. The boy is noted to be a notorious liar, but he was right when he said that [[spoiler:he saw Michel earlier in the movie]]. So is he lying, or has he really [[spoiler:seen a ghost? Or did Christina survive her attack, just like Michel faked his death?]]
%%* MindScrew
* NothingIsScarier: The tension when Christina is wandering through the deserted halls of the school at night, looking for Michel, is incredible.
* NotQuiteDead: Possibly. The film hints that [[spoiler:the wife might have ''survived'' her heart attack. (Or that the kid saw her ghost. Or that the kid is a liar.)]]
* ObfuscatingStupidity: Fichet, the detective, employs a bit of this. (More than one observer has noted the character's similarity to Series/{{Columbo}}.)
* PoliceAreUseless: It's good that Fichet heard [[spoiler:Michel and Nicole discussing their plot]], but it would have been better if he'd stepped up before [[spoiler:Christina keeled over and died]].
* RapeDiscretionShot: The film implies that Michel rapes Christina after the dinner with the fish.
* ReverseWhodunnit: What happened to Michel's body? What's going on?
* ScreamingWoman: Christina, when the lights go out just after she finds Michel's name written over and over on the typewriter during the climax.
* SlippingAMickey: Michel is given sedative-laced whiskey to drink so he can be carried to the bathtub and drowned.
* SpookyPhotographs: Michel's ghostly face appears in the class portrait.
* TwistEnding: [[spoiler:Michel and Nicole have been in cahoots all along.]]
* WouldHitAGirl: Michel slaps Christina after she spills alcohol on his suit -- it's drugged, and she was trying to stop him from drinking it. She then [[LaserGuidedKarma goes ahead and lets him drink]].