Fun for Three (1974)

Sinopsis: Martine Bressac is released from a psychiatric clinic after a year's treatment and is driven home by her chauffeur, Mathias. She is welcomed by the demented hunchbacked gardener Malou and the mute servant girl Adèle, and impatiently demands the key to her mysterious private chamber. There, set out like exhibits in a waxwork, are the bodies of beautiful girls frozen in postures of terror on the point of death. With Mathias' help, Martine has just added another girl, a prostitute, to her collection when her husband and accomplice, Charles, arrives home with slides of a further prospective victim: Cécile the virginal daughter of a diplomat...