Cottbus, DDR, Cottbus, Germany. Cottbus or Chóśebuz is a university city and the second-largest city in the German state of Brandenburg after the state capital of Potsdam. With around 98,000 residents, it is the most populous city in Lusatia. Cottbus lies in the Sorbian settlement area (Serbski sedleński rum) of Lower Lusatia and is the second-largest city on the River Spree after Berlin, from which it is situated around 125 kilometers upstream. The city is located on the shores of Cottbus Eastern Lake. From 1949 until German reunification in 1990, Cottbus was part of the German Democratic Republic (East Germany). From 1952 to 1990, Cottbus was the administrative seat of Bezirk Cottbus.