Vertical social differentiation is presented in the recent literature as an important element of reduced segregation in South European cities, and the supporting evidence originates mainly from Athens. The authors of this article question the claim about the common form and function of vertical social differentiation across South Europe, as well as its opposition to community segregation, and try to reveal the specificity of the processes leading to its formation in Athens. Since the mid‐1970s, the dominant process of urban growth in Athens has been middle‐class suburbanization. This process has reinforced community segregation and, at the same time, has triggered a filtering‐down process in wide areas around the CBD, formerly occupied by upper and mainly intermediate professional categories. Interclass vertical segregation has subsequently appeared in these areas, where intermediate professional categories and lower middle‐class households are now predominant. The fact that these areas do not represent a real choice for any of their resident groups shows that this vertical cohabitation has been the unintended consequence of changing segregation patterns, and hardly the outcome or the corollary of a growing process of sociospatial homogenization.