Hi Oliver,
Thanks for using our plugins and I will try to help out as much as I can.
While we do not have a way to filter along the lines you suggested you could use the Events Location Search to accomplish this.
If you do a search for Germany the url will change to represent that search. You could then use that url as the link from the German version of your site.
That should get you close to what you are looking for.
Another method could be to add a custom filter to the filter bar. This thread has the start of such method.
Adding Custom Filter to Filter Bar
However, it is more involved then the first option and we can help out with the first step, but would be unable to troubleshoot the entire process.
If you have any follow up questions let me know.
Thanks