It is actually illegal in Germany to turn a surname into a given name. You cannot have a child named something like Schmidt or Mueller in Germany.
Of course there are some surnames which have exactly the same form as given names, usually because they indicate that you had an ancestor with that given name, though rarely because the given name and surname have the same spelling by coincidence. Therefore there are examples of people in Germany with surnames like Karl, which are also common given names.
But you cannot turn a surname which has never been used as a given name before into a child's first name in Germany. It's not allowed.
The custom of turning surnames into given names is more established in English than any other European language. You can find some examples in France, however: Regis, Chantal, Foch, and a few others that have become given names in France because of admiration for saints or military and political figures who had those surnames.