Cosi Dolce, Cosi Perversa (aka So Sweet, So Perverse) (1969)

A wealthy married Parisian businessman (Jean Louis Trintignant) falls for a troubled blonde (Carroll Baker) who lives in the flat above his. He attempts to help her free herself from her sadistic lover (Horst Frank) but only succeeds in finding himself as part of a diabolical plot. Directed by Umberto Lenzi, this Italian giallo is the spawn of Clouzot's DIABOLIQUE (1955). As an imitation, it's actually one of the better ones. If you've seen DIABOLIQUE, it shouldn't take much for you to figure out who's who and who's doing what to who. It's the second of the four films Lenzi made with Baker and I found it more satisfying than their initial effort, ORGASMO. Baker does well playing two very different aspects of her character while Trintignant lends a likable dignity to his manipulated lover. With Erika Blanc, Helga Line and Beryl Cunningham.