A good bourgeois household in the suburbs of Nantes,Philippe(Benoit Magimel) is a salesman who lives with his widowed mother,Christine(Clement) and 2 sisters,Sophie and Patricia.He is fearful of violence and over solicitous to his mother.Sophie the eldest sister is getting married to the nerd Jacky.Christine does hairdressing at home to earn some spare change.Patricia is a wild child staying out late,smoking and drinking too much,mixing with the wrong sort.Christine has met a new man Gerard(he doesn't like dogs).A local woman has been murdered(on TV news).
Philippe falls in love with Senta(Laura Smet),one of the bridesmaids at his sister's wedding.Love at first sight.Philippe spends all his nights with the mysterious Senta,in her strange basement of her step-mother's apartment.He neglects his mother and younger sister.Senta's love is exclusive and demanding.She is an actress and model waiting for work and auditions in Paris.Philippe questions her lack of plays among her books. She is a fantasist story-teller(liar and psychopath) and demands they both prove their love for each other,they will have to kill somebody for each other(as well as write a poem,plant a tree,have sex with their own gender).
Philippe thinks this is a joke,but claims he has killed a man(having read it in the paper),the down-and-out,who sleeps inside the exit to her grounds.Senta does likewise,thinking she has killed the man Gerard,who jilted his mother.There are many side characters,like Gerard, Jacky and a stone head statue(Flora) that are all woven into this tale.L'Amour fou brings out the tension and inner conflicts in Philippe.Senta is a basement creature who lives in the shadows with her obsessions reeling Philippe into a dark maelstrom of emotions he finds it hard to get out of or escape from.A dead woman turns up in Senta's house.Rendell translates well into French and Spanish films.Chabrol keeps this pot stewing with many twists and turns as suspense simmers.