The Catman of Paris(1946)

BEWARE! A MONSTER IS LOOSE!

When author Charles Regnier returns to Paris with a best-selling book that criticizes the government, he's tormented by frequent blackouts. After a mysterious cat-like creature slaughters people close to him, Charles is suspected of murder. Charles fears that he is the beast, but his paramour Marie and best friend Henry, believe he's innocent... until the creature begins to stalk Marie.