This artwork is by Franz Wilhelm Seiwert (1894-1933) who was a member of the Cologne Progressives who hated Hitler. He fled to the German mountains after Hitler took charge, but was brought back to the city by friends due to illness and Seiwert died on 3 July 1933.
The Cologne Progressives were artists and they were political, focusing on the rights of the workers. This artwork was painted by Seiwert in 1927 and the museum is using it to represent the entire movement which also included artists such as Gerd Arntz (1900-1988) and Heinrich Hoerle (1895-1936).
The works of this group were defined as “degenerate art” by the Nazis and promptly removed from museums and generally banned. Nearly all of Seiwert’s works in Cologne museums were destroyed, so it’s perhaps fortunate that this particular painting has survived at all.