As a part of the 1939 Nazi-Soviet Pact, Lützow was sold incomplete to the Soviet Union in 1939, where she was renamed Petropavlovsk and then Tallinn. Incomplete when Germany invaded, she was re-equipped as a floating gun battery. After being shelled and bombed at Kronstadt Bay, near Leningrad, she sank. By 1943, she had been raised and renamed as Tallinn and used again for artillery support. Plans to complete her as a cruiser were abandoned for economic reasons (cost of repairing her were estimated at par with construction of a brand-new Kronshtadt class battlecruiser), and she was used as a static training ship until 1950, when she was scrapped.
The name Lützow was subsequently reused to rename the German pocket battleship Deutschland.