Otto Schmalz, Plan for a Royal Summer Palace, 1886
Otto Schmalz (1861-1906) was a minor German architect whose most important surviving buildings are courthouses and offices for the Prussian state. When he was a young assistant - that is, at the time he did these drawings -- he worked on the imperial palace in Strasbourg (now the Palais du Rhin) and other princely residences. But he never got to build his masterpiece.
Now, though, the Architecture Museum of the Technische Universität Berlin has scanned all the drawings and put them online in a wonderful zoomable format, so you can peruse them at your leisure.
I'm not sure what you would call this style; historical pastiche?
The only piece in color is the entrance hall plan below,which I believe was the cover of the plan book.