Maybe it is Albert Rögner, Nürnberg.
When you google the name you will find several Albert Rögner.
First hit is a guy born on 22. January 1925 who died about a year ago on 30. November 2015 in Fürth.
That might have been the late owner of this piece.
I used to live in Fürth (next to Nürnberg) for 15 years.
But I am not 100 % sure about the last name Rögner.