Hello. This post caught my eye because I've studied the German language and have traveled to Germany (never operated there, though).
You might find the following website handy:http://www.darc.de
It is the website of the Deutscher (German) Amateur-Radio Club. When you first get to the website, it will be in German. Click on the flags in the left-hand corner. Then click on "English Website" at the end of a long list of the club's website names in different languages.
I didn't take the time to explore the site, but it might get you to some links about operating, many of them probably with English versions of their websites.