As Daryl already uploaded John303's photos, here is just the ad for the Remo Populär from the ca. 1930 A.Frank, Hamburg, WUM export catalog:

You may find the Gebr. Rempt patent DRP 443437 here:
https://depatisnet.dpma.de/DepatisNet/de...1&xxxfull=1
Heinrich Böker did not make these guns, he merely exported John's example. The gun was made by Gebrüder Rempt, Suhl, trademark REMO. Böker's home Remscheid is the German center of hardware making with several export houses. Just as Suhl and Zella-Mehlis were the German capitals of gunmaking and Solingen of blades and cutlery.