Buffet Froid (1979)

Black, black, black is the colour -- not of my true love's hair but of this French comedy (also known as "Cold Cuts") which is one of several unusual films that the young Gerard Depardieu made with the director Bernard Blier.  They actually star together in this one which concerns itself with what can only be described as casual death and murder.  It opens in the Paris Metro where Depardieu accosts a mild accountant whom he later finds murdered with his own knife; however he doesn't think that he did it.  Soon his wife is found murdered and her killer ingratiates himself into the casual circle which includes Despardieu and Blier -- the only two tenants in a high rise block.  Blier is a police inspector but is far more concerned with crimes other than murder, which is just as well as the dead bodies continue to pile up.  All of the characters are 100% sociopathic or at least completely distanced from what normally constitutes modern morals and all the happier for so being.  By the end there is no one left bar a young woman only recently arrived on the scene as each character falls victim to some sort of perverse justice.