After 1933 her brand of political cabaret was no longer permitted and she found herself subject of a Berufsverbot (government work ban): she left Berlin and supported herself as a regional (unnamed) radio announcer.
She was accepted at the prestigious Stern Conservatory (today part of the Berlin University of the Arts), and quickly acquired the potential to build a career as an oratorio singer.
Katharina preferred to engage with the more bohemian world in the western part of Berlin, with its coffee houses and artists' districts that clustered around the (at that time complete) Kaiser Wilhelm Memorial Church.
[1] It was Karsten Kühl who mentioned to his young wife that he had heard that the established cabaretiste Rosa Valetti was planning to set up her own "literary cabaret" upstairs, directly above the Café des Westens.
But within this circle there was one new friendship which would be more important and long-lasting than any of these others in building and sustaining her artistic career: according to one commentator, for Kühl's idiosyncratic performing style the couplets penned by Kurt Tucholsky resonated just as finely as the songs, chansons and ballads of Mehring or indeed Brecht.
That was the context in which Trude Hesterberg was able to entice Kühl to work at her cabaret, the Wilde Bühne in the Tingel-Tangel-Theater [de], at which (again) Kurt Tucholsky was a regular patron.
In February 1924 "Tucho" accepted an offer from Siegfried Jacobsohn which involved moving to Paris as a theatre critic for Die Weltbühne and the Vossische Zeitung, but he retained in frequent contact with her, both on account of his regular trips home to Berlin and through an animated exchange of letters which was at once professional and friendly.
[2] She also enjoyed professional success on the Berlin theatre stage, appearing on 31 August 1928 at the Theater am Schiffbauerdamm in the premiere of The Threepenny Opera by Kurt Weill und Bertolt Brecht.
Kühl and the other performers made no secret of their hostility to Nazism and after the power seizure in January 1933 many of the better known cabaret celebrities disappeared overnight, turning up abroad a few weeks later.