Saar was the first purpose-built submarine tender of the German Kriegsmarine, and served throughout World War II.

The ship was laid down on 19 September 1933 at the Friedrich Krupp Germaniawerft shipyard in Kiel and was launched on 5 April 1934.

Saar was sailed by a German crew to Cherbourg, where on 17 January 1948 the vessel was recommissioned as Gustave Zédé (A641) of the French Navy.

After sea trials, she received further modifications, and on 13 May 1949 arrived at her new home port of Toulon, where the Groupe d'Action Sous-Marine (GASM), the French submarine command, was based.

[3] At 11:25 on 26 February 1976, the submarine Doris sank Gustave Zédé as a target with an E14 torpedo in the Mediterranean Sea south of Marseille in position 42°30′N 5°24′E / 42.500°N 5.400°E / 42.500; 5.400.