Do you help me to find the title of an old movie?

I’m looking for the title of a b/w movie (40’s/max50’s). I remeber the final scene: in a luxurious living room some dressy men and a woman excitedly argue until she extracts a pistol and shoots, killing, one of the men; soon after she phones the police saying something like: “come, I have just killed a man”... and the film ends. Thanks in advance!