In central Africa, a combination of several types of major geo-hazards threatens the highly populated area centred on the Lake Kivu Basin and the Virunga Volcanic Province. Contributing to Disaster Risk Reduction (DRR) policies not only go through hazards mechanisms analysis, but also through vulnerability assessment. This paper stresses the methodological choices made to target vulnerability assessment in a context of scarce and unreliable data. We discuss here the various stages we have overcome and the analyses conducted at the local scale, i.e. on targeted urban sites. The cities of Bukavu and Goma (Republic Democratic of Congo) count about 800,000 inhabitants each, and catastrophic events are frequently recorded. As a result of our analysis, grounding vulnerability assessment exclusively on a general definition seems not appropriate. Relevant peculiarities of the studied area should also be taken into account in vulnerability and risk assessment. Our research contributes to increase the relevance of DRR policies for risk-exposed populations. Following, one of our main concerns will be to challenge stakeholders who have to face numerous other issues on a daily basis, such as security, land issue or resources.