Based on two illegal occupation situations, one in Hong Kong, and the other in Caracas, this thesis proposes a foremost methodological and comparative appartus, as well as new theoretical terms to analyze the conflictual dimensions of the production of space, and to go beyond the binary spatial categories «formal/informal» with which certain practices and territoriality are generally interpreted in most countries located in the Global South. In the first situation, where a street hawker occupies a sidewalk in Hong Kong, an investigation into an «urban anomaly» begins. It is based on the recording of « material traces », and highlights the process of the small shop of only a few square meter’s programmed disappearance, juxtaposed to one of the largest construction sites that the Asian metropolis has ever known. In the second situation, the occupation of abandoned urban buildings in downtown Caracas, the large amount of ethnographic material that has been compiled enabled the tracking of the popular and polyphonic history of social movements by revealing the « memorial trace » of urban struggles for their right to the city and housing in Venezuela in the 2000s. The analyses show that, if not eradicated, occupations in urban centres and the « normative discordances » that characterize them are negotiated, transformed and then integrated into the city from the « blind spots » during the planning process to give rise to an « occupation urbanism ».