Chabrol, who joined his French New Wave contemporaries with self-financed films, is a subtle reader of social masks and a sharp-eyed pessimist. The story of boredom in a marriage, in bed and in the relationship, accompanied by infidelity, has spawned countless derivatives. Chabrol does find the unforgivable in the ordinary, so that even a drawn-out “bonjour” lands like a slap in the face.

An elite family has secrets to keep. Hélène goes into town to visit the hairdresser and go to the cinema. Or so she tells her husband Charles, an insurance broker. Their days pass without passion, in glacial exchanges about their desires and commitments taken for granted. When they try to turn each other on, the air in the room feels numbingly cold. Charles hires a private detective and soon has his suspicions confirmed – Hélène is living a double life, and he has a capricious plan to make her “atone” for her offence.

We sometimes wish that a film character would go unpunished for their crime, or at least find some possibility of redemption. Chabrol assigns this role to his creative partner, the exceptional actress Stéphane Audran, who embodies more than just a “trophy wife” – she is a glamorous femme fatale – whose husband, played by Michel Bouquet, seeks revenge on her lover. The film is often hailed to be the pinnacle of Chabrol’s career – in it irony moves in lockstep with psychological lacework, since the director was concerned not merely with who cheats on whom and with whom, but also with why infidelity reveals the inescapable fate of the characters. “I’m not pessimistic about people in general, but only about the way they live”, the filmmaker has said.