Written in French. The Grand Palais immersif offers to (re)discover Alphonse Mucha (1860-1939), a major painter-philosopher of the Art Nouveau movement, by taking advantage of the efficiency of digital tools to look differently at the creations of this outstanding poster artist who had himself, in his time, seized the modern means of communication. This Journal, carried by the lively and didactic style of Vincent Brocvielle, wishes to put a special emphasis on Mucha's legacy: from the pacifist "Flower Power" movement of the Sixties, through Japanese manga, superheroes, street