The analysis of segregation of migrants not only was one of the starting points of Chicago School of urban sociology, but is up to now still one of the central aspects of urban and spatial sociology. Moreover, the debate about the spatial concentrations of specific migrants in policies, administration and the public is rather emotional and normative. Spatial concentrations are refused mainly without any exception. However, this position is lacking a proper statistical evidence for either support or prohibition of social cohesion. There are some reasons for this mismatch: First of all, ‚nationality‘ and ‚migration experience‘ are no sufficient categories of social sciences, as the correlation with relevant attitudes and behaviour is small (and obviously shrinking) due to the internal variance within these broad groups. Second, supposable neighbourhood/place effects of neighbourhoods with high rates of foreigners are not systematically analysed up to now. Third, empirical results of other studies can hardly be used in a simple comparative analysis, as these results are highly dependent from place and time. Forth, considering the impact of social media and the high mobility rates within cities, the immediate neighbourhood cannot be understood as the almost exclusive area of socialisation. Finally, deficits of migration sociology are mentioned, particularly as no proper socio-spatial typologies are developed in this field so far to describe and explain attitudes and behaviour which are relevant for integration.