In Portrait of Zacharie Astruc, the viewer sees a distinguished man dressed in formal attire. The colors are rich, with deep reds and warm browns dominating the palette. The background is softly blurred, focusing attention on the subject's face.

The expression is serious yet contemplative, inviting the viewer to ponder the man's thoughts. The painting is executed in oil on canvas, a medium that allows for vibrant colors and detailed textures. Henner's brushwork is smooth, creating a lifelike representation of Astruc. The play of light and shadow on the face adds depth and dimension to the portrait.

The overall composition is balanced, with the subject positioned centrally. Jean-Jacques Henner was known for his portraits that often highlighted the individuality of his subjects. Portrait of Zacharie Astruc is a notable example of his Realism style, capturing not just the likeness but also the character of the sitter. Interestingly, Astruc was a prominent art dealer and a supporter of Henner's work.

This connection adds a layer of significance to the portrait, as it reflects their professional relationship.