...la main à couper (1974)

Hélène Noblet leads a peaceful life: a doctor husband, Georges; two well-behaved children, Daniel and Nadine; an antique shop that she runs for pleasure with a friend, Pascale; a lovely house; money... and a lover, Philippe, younger than she is and a friend of her son’s, whom she meets every Tuesday. Everything would be perfect if, one Tuesday, Hélène did not find Philippe murdered. After retrieving a compromising notebook, Hélène notices, as she leaves the building, that her car has been stolen... only to find it where she left it the next day, after reporting it missing to the police. The compromising notebook, however, has vanished from her bag. The murder is now splashed across the front pages. Daniel admits to Moureu, the inspector in charge of the investigation, that he had an altercation with Philippe shortly before his death, making him the prime suspect. Hélène is visited twice by a blackmailer: Henricot. As she is about to pay him the five million she has raised by selling her jewelry, she realizes that someone has replaced the banknotes with newspaper. The young woman panics: the missing notebook, the car turning up again, the switched money... could it be her husband, out of revenge, trapping her in a diabolical scheme? The investigation eventually reveals that Henricot is the real murderer.