In July 1940, the French battleship "Bretagne" was destroyed by whom?

The Battle of Mers-el-Kébir was a British naval bombardment of the French Navy on 3 July 1940. It was part of "Operation Catapult" designed to safeguard Britain's maritime interests after the fall of France to the Axis powers in World War II. The combined air-and-sea attack was conducted by the Royal Navy in response to the Franco-German armistice of 22 June, which had seen Britain's sole continental ally replaced by the collaborationist, pro-Nazi Vichy government.

The new Vichy government had inherited a considerable naval force, including seven battleships. Admiral François Darlan, Chief of Staff of the French Navy, had promised that the French fleet would remain under French control but, since Vichy was seen by the British as a mere puppet state of the Nazi regime, there was serious fear that the French would surrender the ships to the Kriegsmarine (the navy of Nazi Germany), an outcome which would confer a major Axis advantage in the Battle of the Atlantic. So, despite Darlan's promises, Winston Churchill and the war cabinet determined that the fleet was too dangerous to remain intact.

The raid resulted in the deaths of 1,297 French servicemen, the destruction of the battleship Bretagne and the damaging of five other ships.

In retaliation for the attack at Mers-el-Kébir, French aircraft raided Gibraltar on 18 July 1940.