The life space of populations is materialized by the habitat. This habitat spreads with the population increase. In the urban area, the transformation of the habitat is sometimes accompanied by problems like, segregation, risks.., rais- ing the problem of the zone planning. The case of fire risk in the city of Yaounde is mentioned here and calls for an analy- sis, in a context that clarifies on decision making for problems of zone planning. The strategy of approach here is to determine steps of phenomenon analysis, to describe the fire risk in its evolution while unveiling the derived information, which can characterize the urban area; an application is made to the city of Yaounde. At the end of this survey, the elements of definition and characterisation of the fire risk in urban area follow by character- istics of the city zones of Yaounde, taking account fire risk and measures to remedy them have been done. The urban area ensures to populations several functions including sanitary, social, administrative, etc.. Difficulties of management increase with the expansion of the city. Those of developing countries are the main concerned. These man- agement difficulties become more pronounced with the ap- pearance of several problems (poverty, segregation, risk, etc.). Thinking about solutions, it would firstly be necessary, to provide knowledge concerning them. It is the case of fire risks in the city of Yaounde of which we propose to study the complexity of existence in order to provide information of decision-making for problems of urban planning. There is a relationship between fire risk and the elements of habitat; what strategy of risk analysis is necessary so as, to provide information of solution to the problem of zone plan- ning? For that, we have counted all elements of existence of fire risk in their space while following its setting up since the appearance until the occurrence of the fire catastrophe (1). We also propose to the relations and properties between these elements. This numbering leads to the determination of natures, and possible types of entities. This description of existence of fire risk in its environment permits to discover factors of risk (2), including mainly elements of habitat, and to characterize zones and constructions concerned. Looking forward to eliminate these factors, we have proposed solu- tions to the planning of zones.