This article aims to explicitate the Lacanian usage of the notion of das Ding extracted from Freud's Project for a Scientific Psychology (1895). Resuming the idea of an experience of satisfaction we will try to show at which point das Ding, as the Real, is essential to the constitution of the psychism. Moreover, it will be pointed out how the relationship of the infant with the Other can determine a way of dealing with reality marked by the jouissance.