The 2,026 kg of cocaine was found on a ship 226 miles off the coast by naval forces backed by air support from the French air force, the navy said in a statement.
The ship had five crew members aboard, it added.
Drug smugglers typically use West Africa as a transshipment point for cocaine en route from South America to Europe.
In January, authorities in neighboring Gambia seized nearly three tons of cocaine from a shipment of industrial salt originating in Ecuador.
Morocco police on Monday seized one ton and 335 kilograms of cocaine concealed in a container ship in Tangier Med Port.
By Diadie Ba