I've seen someone with this cap last week and I had to get it!
Unfortunately I found it only at one Online Store called www.kleiderkreisel.de
As far as I know this cap is from a popular german singer called "Casper".
This is the cap: https://images.vinted.net/thumbs/f800/0219e_JqbdTYAp9JR1ExEp83ixZ2WM.jpeg?11498712231
It's black with a little blue. On the shield is a flower pattern, and at the crown of the cap is a text saying: "Verachtung", the t is upside down and symbolizes a cross i think.
"Verachtung" is German and means "contempt".
I hope someone can help me!