You can find German crowdfunding platforms by searching "crowdfunding deutschland" in a search engine, or more specifically "crowdfunding roman" (that is, "crowdfunding novel" in German) or something similar.
There are a few media reports (e.g. Deutschlandfunk) online about Swiss author Tim Krohn, who crowdfunded one of his writing projects on wemakeit.com, where he collected 50,000 Swiss Francs. Another of his projects on startnext.com did not gain any financing, probably due to regionally limited appeal.
Author Jasmin Jülicher collected 2,000 Euro on visionbakery.com for her fantasy novel. There are many more examples, and many more platforms. You'll have to compare your options and find the one that best fits your needs.
In the end, all crowdfunding relies on the marketing that you do, and the platform that collects the money is not the most important aspect of that. What you really need is a marketing platform, which could be Twitter (if you have enough followers) or interviews that you do with news media and so on.