Few published studies have thoroughly treated the history of European planning practices in the overseas colonial territories. This is especially true regarding the African continent in general and sub-Saharan Africa in particular. Interest in the indigenous response to the formal organization of the colonial settlement has only been manifest in the last few decades. In addition, French and British colonial policies and practices in West Africa, particularly with regard to town planning, have rarely been analyzed together within the same intellectual framework. This work is concerned with the perception and realization of residential segregation in two major colonial capitals in West Africa: British Lagos and French Dakar. The history and the form of residential segregation in Lagos, a chief port and an administrative and commercial centre, and in Dakar, the capital of the AOF (Afrique Occidentale Francaise) Federation, are traced from the establishment of the official colonial rule in the mid-nineteenth century to the inter-war period. The focus on residential segregation as a crucial aspect of colonial urban planning directly relates to colonial discourses, municipal politics and indigenous conceptions. Rather than a schematic and somewhat simplified model of segregation, comparative aspects are stressed here, offering a more diversified view of this phenomenon. Urban policies also served purposes other than mere separation of various ethnic groups, and a more complex definition of segregationist schemes is needed, referring to conceptual and actual nuances of spatial divisions and hierarchisation.