Spatial data production and diffusion have been going through major developments since the digital transition of the 1990s, which translated in the emergence of new institutions organising their circulation: Spatial Data Infrastructures (SDI). In this new informational system, the notion of " sharing " is at the centre of the debates. But it is a contradictory ideology carrying divergent societal projects: some may think it encourages public transparency and informational democracy, and others that it compensates the State's inadequacy by favouring the participation of citizens in managing territories. This article on information geography offers a critical reading of the new modes of circulation of institutional spatial knowledge, by understanding spatial data sharing practices within SDIs, by comparing European and South American cases and analysing their effects in terms of spatial justice: citizens' access to information, improvement at territorial level of information coverage, mapping capacities of local specificities. SDIs seem to contribute especially to the reconstitution of the State's role, where in certain contexts they can favour the democratisation of territorialised public policies, and reinforce national sovereignty. They turn out to be far more paradoxical in their local effects: implementing a sharing process sometimes supposes a reinforcement of the exclusion forms of certain groups, and a normalisation preventing the expression of genuine territorial representations.< Réduire