Horst Sagert, stage curtain for J. Schwarz' The Dragon (detail)

Andre Muller, from Gebrauschsgraphik (March 1967):

Horst Sagert, a former student of Heinrich Kilger, has come to fame through two stage designs he created at the Deutsche Theater in East Berlin for stage director Benno Besson: namely for the production of Tartuffe and for the production of The Dragon [Der Drache, by Jewgeni Schwarz]. Both productions have meanwhile become famous the world over, and that not least of all thanks to the stage designs. Horst Sagert possesses a special qualification which hardly another scenic artist shares with him: he is a painter.

From Besson's obituary in the Guardian:

"In The Dragon, the fire-breathing monster always brought gasps from audiences, and Besson created a fantasy world with a veritable labyrinth of narrow alleys, triffid-like trees and baroque, sugar-iced castles."

I hope I can dig up more of Sagert's work. Buhnenbilder und Figurinen zu Jewgeni Schwarz' Der Drache is a cool little book (about 4 x 7 in size), and can still be found online for not much money. Some of the scans come from Gebrauschsgraphik (including the Tartuffe image), due to the difficulty of scanning spreads in the book. This March '67 issue also includes four images from Sagert's stage designs for Rise and Fall of the City of Mahagonny (Brecht/Weil) but unfortunately they're black and white (like most images in Gebrauschsgraphik, maddeningly).

Horst Sagert, stage curtain for J. Schwarz' The Dragon (full)

Horst Sagert, stage design for Jewgeni Schwarz' The Dragon (first scene: House of archivary Charlemagne)

Horst Sagert, stage design for Jewgeni Schwarz' The Dragon (2nd scene: Market-Square)

Horst Sagert, stage design for Jewgeni Schwarz' The Dragon

Horst Sagert, stage design for Moliere's Tartuffe

Horst Sagert, technical drawing for J. Schwarz' The Dragon

Horst Sagert, Buhnenbilder und Figurinen zu Jewgeni Schwarz' Der Drache, cover, 1971