The Phoney(1975)

Original title: Le Faux-cul

While the President of a West African Republic arrives in France to sell uranium to the State, spies from around the world are on hand to thwart the transaction. France then decides to put one of its worst agents on the case, a certain Maxime, who has a very loose tongue. All they have to do is send him false information, hoping that it will fall into the ears of their enemies...