The Catman of Paris (1946)

When author Charles Regnier (Carl Esmond) 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 (Lenore Aubert), and best friend, Henry (Douglass Dumbrille), believe he's innocent ... until the creature begins to stalk Marie (from Netflix description).