I have traveled to Berlin a few times for work, and I didn’t feel out of place in a Kippa. Though it was winter so some of the time I was in a ski-cap.
Thanks for the reply. Berlin has a vibrant jewish community and according to news thousands of young Israeli immigrants settle there every year,…so I guess goyim in the federal capital are more used to kippa-wearing jews. I’m not sure about cologne area though,…so I’ll play it safe and stick to wearing a nondescript headwear.