Brussels is the capital of Belgium, of the Flemish region, of the French Community, of the Brussels capital region and of the European Union - which means it has to deal with a complex system of competencies. Urban planning is also characterised by the superimposition of so many different layers.
The general trend in the spatial configuration in the Brussels capital region is similar to that in other European capitals of the same size. Increased welfare has led to a growing need for space and thus to suburbanisation and social and spatial segregation within the metropolitan area. The Brussels capital region has a higher degree of social and functional mix (in age, income classes, spatial distribution of activities) than most European cities. The reason is the relatively low proportion of social housing units in the total housing stock: in Belgium (and Brussels) the percentage is 8 per cent, whereas in neighbouring countries (and their capitals) the figure is at least 35 per cent. Large-scale housing estates concentrating lower-income classes (Großsiedlungen, grand ensembles, new towns) are almost non-existent in Brussels. These population groups stay in the city centre and the nineteenth-century ring around it in old, poorly renovated, low-comfort buildings and thus pay cheap rents. But they are mixed with higher-income groups because of the recent spectacular growth of couples without children preferring to live in the city: Their preference for the city has resulted in a recent increase of the innercity population and a spontaneous revival of inner-city quarters. The low degree of publicly owned housing indirectly causes strong suburbanisation. Seventy per cent of Belgians own the house they live in.