Quintessential thirties exotica which is a remake of a silent starring Ivor Novello, based on his own stage play. It's similar to the French classic Pepe le Moko, but set in Montmartre rather than the Casbah. Novello actually got there first... and while this isn't as poetic, or as good, there's plenty to enjoy for fans of romantic melodrama.
Anton Walbrook takes over as the Rat in his English language debut, and he's pretty good. He is the mysterious and dangerous jewel thief who preys on the rich women of Paris, and then retreats back into the labyrinthine slums of the underworld, to his coterie of sex workers and cutthroats, to break a heart or essay a tango.
Ruth Chatterton is the slumming American tourist who falls for the charismatic anti-hero. She is largely forgotten now, but was a huge Hollywood star in the early talkies. By 1937 she was a little matronly and Bette Davis was getting her usual roles so this was her last film. Rene Ray is better as the teenage ingénue the Rat protects.
Of course, it's all atmosphere, with the fascinating criminal/heartbreaker residing in a distressed garret on the skyline of bohemian Paris. Which naturally he accesses via the window. It's the sort of role Valentino once specialised in; a febrile illusion into which we briefly escape from humdrum realities.