The article questions the appropriation of existing urban planning and management tools in Sub-Saharan Africa, through a multiple case study: the implementation of a land information system (or simplified cadastre) in three cities in Benin. An ethnographic exploration of the use of the tool is conducted. The first section presents the historical context of the design of land information systems, framed by the urban management paradigm, and unwarranted confidence in new technologies. The second section presents the theoretical framework and the methodology of the research, inspired by public policy analysis and development anthropology. The third section describes findings of the multiple case studies. A vicious circle is highlighted, made up of: lack of political support, obsolescence, and decline of cost-effectiveness. The fourth section discusses the results of the ethnographic inquiry. These are, essentially, the interpretation of the paradoxes, blockages, and conflicts in the implementation of the tool in light of social, political and economic dynamics that take place at the local level, although unexpected by the creators of the tool.