From considerations on the cognitive representation of urban space, an experiment is set up to induce the representation of Sherbrooke city, as shared by its population. It is assumed 1) that a cognitive process arises between the stimuli from urban space and the response of the individual evolving in it, 2) that this process produces a genuine inner reconstruction of urban space, as perceived, known and represented in his thought by an individual. In his empirical research, the author submits that it is possible to infer from a population some common cognitive representation of urban space, and shows that urban space is represented in the thought of the population as an organized structure. This is because urban space is a content socially and ideologically produced, valorized, structured by urban practices. This leads to an interrogation on the meaning and the places of urban intervention.