I have 281 german makes before '45.
I don't have the Beaulieu Encyclopedia.
You say it's a '10, in Germany, a city that was inside former eastern germany, and now is inside Germany, but not Berlin. Today the city is known for spa. The maker excisted three years or less.
I'm belive I have no chance on this one. In Wismar, there was a make, Podeus, but they excisted to '18.
In Aachen, Scheele was from '99 to '10.
Vogtland is too known, and I'm unsure if they was in east, or west. Also one of my sources tell '10 to '15, and he is German. Other places I read '10 to '13.
The last option I have is Westfalia, but they also excisted over a 5 year periode.
Looking forward too see what this is, as it will be something not well known.