'Frankfurt' was a German unrealised naval undertaking to strengthen the mine barrage system, in effect extending the German coastal mine barrier northward into the North Sea to the west of German-occupied Norway (4/6 December 1940).

The ships which were to have been used in this undertaking were the light cruisers Nürnberg and Köln, and the torpedo boats T-1, T-5, T-8 and T-12.