There's No Tomorrow (1940)

Evelyne Morin has known much misfortune in her life. Widowed, after being married to an unscrupulous adventurer, she ends up working as a call-girl in a Montmartre nightclub just so that she can bring up her young son. But Evelyne has hopes of escaping from this degrading life. One evening, she meets Georges, a Canadian friend, whom she once considered marrying. Since she last met him, Georges has become rich and highly respected as a doctor. To conceal her downfall, Evelyne pretends to be a respectable woman, with the help of Paul Mazuraud, an odious man who provides her with the wherewithal for her to keep up this deception. When her son unintentionally gives the game away, Evelyne places him in the care of her Canadian friend and then fades away into the fog...