Jean Louis Barthou (25 August 1862 – 9 October 1934) was a French politician of the Third Republic.
Barthou served as Foreign Minister in 1934. He was the primary figure behind the Franco-Soviet Treaty of Mutual Assistance of 1935, though it was signed by his successor, Pierre Laval.
It was assumed that Chernozemski hit both victims. But in 1974, forensic examination found that the bullet that struck Barthou was not a 7.65 mm caliber bullet and could not have been fired from Chernozemski's gun. It was an 8 mm bullet, the same caliber used by the Marseille police, and must have been fired at Chernozemski by one of the escort.
In 1957, the East German newspaper Neues Deutschland ("New Germany") published supposed correspondence between Hermann Goering and Hans Speidel. In 1934, Speidel was an assistant to the German military attaché in Paris; in 1957 he was high-ranking NATO commander. According to the supposed correspondence, the death of Barthou was intentional, and the assassination was planned and prepared by Germans with Hitler's personal approval. The story was repeated in a book and in the film Unternehmen Teutonenschwert ("Operation Teutonic Sword"). This claim has been disputed as propaganda.