It is with regard to the painting "Nude descending the staircase" that Alain Jaubert has chosen to evoke the work of Marcel Duchamp. It is 1913, in New York, and the work of this 25-year-old young man, which depicts different moments of the action of the same character, is causing a stir. Cubists do not recognize it as one of their own, and traditionalists see it as a dangerous iconoclast.