This analogy fails, imo. From the Strafgesetzbuch sec. 86a:

>> Subsection (1) shall not be applicable if the means of propaganda or the act serves to further civil enlightenment, to avert unconstitutional aims, to promote art or science, research or teaching, reporting about current historical events or similar purposes.

I'm no lawyer, and know almost nothing about German law, but this wording would appear to preserve an exception for cases exactly like this one, i.e. artistic or historical portrayal.