The movie's title "The blue swards" refer to the logo of the Meißen porcelain, which shows two blue swards being crossed. Those are also shown in the intro.
The hotel in the earlier scene titled "Hotel König von Portugal" (King of Portugal Hotel) actually existed in central Berlin on the east bank of the Spree. It was found in the 18th century and got its name after King Frederic Wilhelm I invited guests from Portugal there. It was destroyed at the end of World War 2 after the allies bombed Berlin.