qnli question: When did poster art become an important art form? sentence: Poster art also became an important art form in Paris in the late nineteenth century, through the work of Henri de Toulouse-Lautrec, Jules Chéret, Eugène Grasset, Adolphe Willette, Pierre Bonnard, Georges de Feure, Henri-Gabriel Ibels, Gavarni, and Alphonse Mucha.