Weissenhofsiedlung Haus Le Corbusier

Pierre Jeanneret / Le Corbusier, Weissenhof-Museum Stuttgart, 1927

Kathreiner Hochhaus by Bruno Paul

    Architekt: Bruno Paul 1928-30, Berlin Schöneberg

Haus der Buchdrucker by Max Taut (1924-26)

Haus des Deutschen Metallarbeiterverbandes (IG Metall), by Erich Mendelssohn, 1928–1930

Alexanderhaus und Berolinahaus by Peter Behrens

Peter Behrens is one of the main figures of early modern architecture.
Around 1900, he brought modernism into (industrial) architecture, invented Corporate Design by creating everything from the typography to ashtrays and the actual factory building for major german enterprise AEG.
He was one of the founders of the "Deutscher Werksbund" and "The Ring", Le Corbusier, Gropius and Mies van der Rohe learned from and worked with him.
In the 30s he was entrusted to recreate Alexanderplatz, the 2 buildings left by him are the Berolinahaus and the Alexanderhaus:

Mossehaus by Erich Mendelssohn

In 1922, Erich Mendelssohn, who had become world-famous with the Einstein-Turm in Potsdam, was asked to enlarge the existing building in the Schützenstrasse (Mitte) and gave it a modern, dynamic shape.

Bruno + Max Taut: Haus des Deutschen Verkehrsbundes, Warenhaus der Konsumgenossenschaft (Max-Taut-Haus)

Haus des Deutschen Verkehrsbundes

by Bruno and Max Taut, 1927-1930. Engelbecken, between Mitte and Kreuzberg.

nearby, going down the "Luisenstädtischer Kanal" to Oranienplatz is the former "Warenhaus der Konsumgenossenschaft", built between 1930-33 by Max Taut and Franz Hoffmann

 

Bruno and Max Taut were important personalities of Berlin's inbetween-wars-architecture. The elder one, Bruno, was an important motor for several "Siedlungen" and founded the artistic network „Die gläserne Kette“, (which later became "the Ring"), publishing a Revue and exchanging thoughts with the major contemporary architects like Gropius, Scharoun, brothers Luckhardt.. . Max is best known for his bureau buildings.

Die Weisse Stadt Reinickendorf

Siedlung from the late 1920s, planned by Martin Wagner (who also planned Siemensstadt, Hufeisensiedlung and Onkel-Tom-Siedlung, amongst other major projects of the 1920s), built by Bruno Ahrends, Wilhelm Büning und Otto Rudolf Salvisberg.
My favourite section is the one by Ahrends: