This articles analyses the presence of African and Asian migrants in the Beirut rental housing sector and reviews the situation in urban marginal districts and their geographical transformation due to, and revealed by, global migration. It takes a multi-layered approach involving three groups of actors: tenants, landlords, and local authorities. The first group come to Lebanon to take up employment contracts and are usually assigned to unskilled jobs. They suffer from discrimination and have few legal rights but they are preferred by people (both Palestinian refugees and Lebanese) wanting to earn money from their properties. Taking advantage of these difficulties, landlords can impose high rents and arbitrary conditions on their tenants. This situation leads to tensions linked to social and identity issues in certain districts in Beirut. The arrival of migrant tenants and the capitalist practices of landlords both present "de facto" challenges in these districts which were developed in order to accommodate the arrival of refugees from Palestine and Armenia and are now incorporated into the city.