"Taking its title from John Keats’s early 19th-century poem, this highly personal melodrama finds Dulac interrogating the archetype of the femme fatale. La belle dame sans merci follows a famous actress who was once seduced and abandoned by a rich man and subsequently resolved to become a “merciless woman,” forever scheming to hurt others (men in particular) in a ruthless yet captivating manner. Dulac challenges the Romantic archetype embodied in Keats’s poem by way of symbolist mise en scène, self-reflexive narration, and her typically associative approach to editing, locating a modern ambiguity within the stereotypical figures of 19th-century art." - Film Society of Lincoln Center

From 1927. Starring Emma Gynt.
You probably wouldn't be watching this if you didn't already know that Dulac directed the first surrealist picture, The Seashell and the Clergyman.
If there's any film that will make you feel sympathy for a woman considering an adulterous affair, it's this one. Without a single intertitle, Dulac brings us into the minds of her characters and shows us the power of the erotic imagination, especially under the sway of loneliness.