French tanker Franche Comté visited the Black Sea according to a letter of the German naval attaché at Istanbul dated 22 December 1939

In his letter dated Istanbul,  22 December 1939 No. 575g reported the German naval attaché to the Oberkommando der Wehrmacht Abteilung Ausland the steamships passing Istanbul. An item reported that the French tanker Franche Comté was armed with 1 gun on the bow and 1 gun and flak at the stern.

Source

Bundesarchiv. German Marineattaché for , Greece, Romania and Bulgaria 1939-1941. RM 12-II/459.