This is really paramilitary/political, but I will bend the parameters to fit it in here.
This is a hyper-rare visor for the Reichsbanner, which was a paramilitary arm of the Social Democratic Party. This organisation fought a 2-front political war, in that it opposed the Communists on the left and the Nazis on the right.
They were banned by the Nazis after they came into power, and most of its senior leadership was arrested (and even executed in some cases).
Have a good look--there are not many of these out there:
Link to Freikorps and Paramilitary Visors in Period Photographs:
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