In Louis Gueymard (1822–1880) as Robert le Diable, we see a striking portrayal of the actor Louis Gueymard. The painting features rich, dark colors that create a dramatic atmosphere. Gueymard is depicted in a theatrical pose, dressed in elaborate costume, embodying the character of Robert le Diable.

The background is muted, allowing the figure to stand out prominently. The painting is executed in oil on canvas, a common medium for portraits in the 19th century. Courbet's brushwork is visible, with a focus on texture and detail in Gueymard's costume. The dimensions are approximately 80 x 100 cm, making it a sizable work that commands attention.

The use of chiaroscuro enhances the three-dimensionality of the figure. Gustave Courbet was a leading figure in the Realism movement, known for his commitment to depicting everyday subjects. This portrait of Gueymard showcases Courbet's ability to blend theatricality with realism. Interestingly, Gueymard was a popular actor of his time, and this work reflects the intersection of art and performance.

The painting was likely created around the time of Gueymard's prominence in the theater scene.