Intended to be used for refuelling in France in 1938, the oil tankers La Seine and La Saône were dry docked in 1939, but their construction was stopped abruptly by the war. Finally put into service at the end of the 40s, they would be used for a time on the line towards Iraq before being taken back by the Marine Nationale (French Navy) for its own use. Since refuelling techniques at sea had developed considerably, the decision was made to transform them into squadron oil supply ships, this complete overhaul requiring gantry cranes to be installed for the fuel pipes. With the tests following this modification proving conclusive and take part in various exercises, even in missions in the Pacific in the Force Alpha. This operation, mobilising numerous ships, was mainly intended to protect the French nuclear test sites of Mururoa and Fangataufa, and would continue for a number of years. Now surpassed by units of much higher performances, La Seine and La Saône would leave the ranks of the Marine Nationale in the mid 70s and cease operation a short while afterwards.