"Le Chef-d'œuvre inconnu" (English: "The Unknown Masterpiece") is a short story by Honoré de Balzac.

With some slight touches of the paintbrush, Frenhofer transforms Porbus' painting such that Mary the Egyptian appears to come alive before their very eyes.

Although Frenhofer has mastered his technique, he admits that he has been unable to find a suitable model for his own masterpiece, which depicts a beautiful courtesan called Catherine Lescault, known as La Belle noiseuse.

Critic Jon Kear argues that Cézanne's own attempts to paint the nude were heavily influenced by Balzac's portrayal of Frenhofer's work.

Picasso was fascinated by the text and identified with Frenhofer so much that he moved to the rue des Grands-Augustins in Paris where Balzac located Porbus' studio.

[5][6] Sidney Peterson's 1949 avant-garde film Mr Frenhofer and the Minotaur was based on the link between the short story and the work of Picasso.