Léon Césaire Auguste Pousthomis was a French illustrator, lithographer, and caricaturist.

He worked mainly in lithographic music publishing (small and large formats), advertising, postcards, and satirical press.

For music publishing, Pousthomis drew in a variety of styles: friezes, romantic or dramatic pointillist landscapes, comic military scenes for Dranem and Bach, caricatures of singers (Ouvrard, Bérard, Fragson, Montel, Mayol, etc.), portraits of women, and realistic animated scenes.

A sergeant in the 69th Infantry Regiment during the Great War, he was killed in the Battle of Verdun in the Hesse Forest near Avocourt (Meuse) on March 28, 1916, at the age of 35.