Paris (AFP) - Kristen Stewart on Friday became the first American actress to win a Cesar, France's equivalent of the Oscars.

The "Twilight" megastar was rewarded for her role alongside Juliette Binoche in "Clouds of Sils Maria".

Directed by France's Olivier Assayas, 24-year-old Stewart plays the personal assistant to a star actress played by Binoche and follows their intense, sexually-charged relationship.