The Prométhée is a French submarine of the class 1 500 tons launched in 1930 in Cherbourg. On July 7, 1932, while sailing on the surface during his tests, the submarine suddenly sank off Cape Lévi (English Channel) for no apparent reason, resulting in the death of 62 of his 69 crewmen and causing a strong emotion in France. The wreck is located the next day but rescue and bailout attempts are unsuccessful. Survivors' testimonies have shown that the sinking is likely due to a sudden opening of the diving purges.