Schebera belonged to the Schapiro conglomerate, just as Dixi did. So it might well be a Schebera body, as they mainly bodied cars from Schapiro's brands: Benz, Protos, Dixi and Cyklon. But Buhne also is a good guess.
About the 23/70 PS designation: Halwart Schrader made a very explicit listing of the Dixi models, covering 36 pages in his "BMW Automobile" book from 1978. A 23/70 PS isn't mentioned there, neither in Werner Oswald's "Deutsche Autos 1920-1945". If you compare the size of other German cars of that age having engines with 23 Steuer-PS (The first Maybach had 22 Steuer-PS), I consider the chassis of the puzzle car too small. And it clearly resembles the Dixi 6/24 PS.