This research investigates how specific colonial urban spaces in Central Africa developed between 1885 and 1960 not only as the result of top-down planning processes but also via social processes within their ‘cosmopolitan’ communities. On the one hand, we study the physical urban form on various scales (city, neighbourhood, street, building) from a translocal perspective to go beyond the conventional historiography that reads colonial planning and building as a process resulting from the mere import from the metropole to the colony. On the other hand, we investigate migration trajectories through a social-demographical analysis to bring to the fore other urban actors, such as Portuguese, Italians, Greeks, etc. We also started to map the shared culture of expertise in building and planning among various colonial powers and how that affected practices in the Belgian Congo. The research focused on two cities, Lubumbashi and Matadi. It builds upon extensive archival research and fieldwork and made use of new forms of cartography and oral history.