Many cities of the South have been facing population growth for several decades. In regions sensitive to landslides, this growth can be an issue when people, often the most vulnerable, are forced to live on unstable slopes. Bukavu (DR Congo) is particularly affected by this situation. However, despite numerous slope instability in areas with very high population density, there is no reliable estimate of the building vulnerability facing these processes. The purpose of this research is to better understand these issues by focusing on a particularly sensitive area of the city. The structured observation of over 450 houses selected in various geomorphological constraints areas was carried out by observing cracks, tilted structures and other deformations. Damage is observed on 55 % of the buildings. The presence of different types of geomorphological constraints does not alone justify the damage to the houses. A changed use of slopes, economic constraints and land use policies that do not integrate the management of natural hazards are also involved. This research is a first step towards the study of vulnerability and the risk associated with landslides. It also allows to make some clarifications in order to improve land management.