The urban sociological research literature primarily focuses on large cities. Issues such as segregation, social inequality, and social urban (neighborhood) development seem to gain significance with increasing city size. Medium-sized cities or even small towns hardly attract the interest of sociologists in this context. With regard to dealing with disadvantaged living conditions, Martin Lenz examines the city of Karlsruhe to what extent sociological theories of social inequality and segregation are relevant for the municipal practice of medium-sized cities. This also raises the question of the application of empirical social research methods in the municipal practice of social administrations, as urban policy – a central assertion of the study – must ensure a balance between sociological theory and municipal self-administration.