On the eve of the celebration of the 90th anniversary of 1929’s CIAM, the city of Frankfurt is again the center of international attention thanks to a project related to housing and the city, which represents, however, the opposite of the experience of Das neue Frankfurt. I refer to the Dom-Römer, the heart of the historical city, destroyed by bombing during WWII, replaced in the post-war period by the Technisches Rathaus, and now “rebuilt” in total adherence to the historical parcel plan as a new residential and commercial district. Regarding mass public housing, with minimal individual dwelling cells and standardized construction conceived by Ernst May, an equally public intervention is now opposed, but with a few individual houses and owned apartments for upper-middle-class customers, unique in their exceptionality, constructed with traditional techniques and finished with craftsmanship, case by case. The modernistic idea of low-density monofunctional satellite neighborhoods on the edge of the consolidated city, based on repetition of typed elements and on correct orientation of buildings in order to grant air and light, at the expenses of a clear definition of public space, is replaced today, in the core the city, by the medieval plan, with its irregular parcels and the narrow, winding dark alleys, high density and multifunctional buildings, and a strongly characterized public space. The positions are of course diametrically opposed also with respect to the roof dispute, which animated architects at the beginning of the 20th century: strictly flat roofs in the new Frankfurt of the 1920s and pitched roofs in the gabled houses of the ancient contemporary Frankfurt. From the parallel between these two experiences, so different from one another that they are almost incomparable, important elements emerge to understand the current debate on the architecture of the European city, particularly in Germany.