Abstract: Charles Le Brun, the first painter of Louis XVI, delivered several speeches in the Académie royale de la peinture et du sculpture and talked about the question of expressing people's passions. He developed his own theory of expression by consulting the Les passions de l''âme by René Descartes. Some scholars think that it was Descartes who influenced essentially the classicist aesthetics of Le Brun and the académie. Others think that Le Brun radically misread Descartes, and thus they depreciate his theory of painting. This article has a different opinion: the theory of expression was formed by reforming substantially the text of Descartes, and in so doing it deviated fundamentally from the latter. Le Brun made the reform on purpose: on the one hand, Le Brun, as a painter, always concerned how to use the visage to express the soul; on the other hand, Le Brun, as president of the académie, internalized the pressure of the institution. By exploring this problem, this article tries to use this detailed issue to reflect the resources, methods, institutions of the French classicist aesthetics during the first half of the 17^th century.

Key words: Descartes, Le Brun, passion, expression, Académie royale de la peinture et du sculpture