International audienceResearch on policies and practices of mediation, valuation and education on open data reveals that the opening of data triggers new questions that carry a fundamental question about the place of data in the functioning of contemporary democracy. The public open data space is determined in negotiating locations and in unclear arrangements. The devices that allow access to these data respond more to a logic of administrative and economic governance than to democratic principles. Thus, for open data to participate in a form of reinvention of democracy in the context of big data, the information and cognitive practices that allow the use of data require complex acculturation actions and the development of data literacy.Une...