Answer: The Luger pistol used 9mm Parabellum ammunition.
Some extra relevant information:
The Luger pistol, one of the iconic firearms of World War II, was indeed manufactured for the German army. This weapon utilized a specific type of ammunition known as the 9x19mm Parabellum. Commonly referred to as the 9mm Luger, the ammunition was specifically designed to be used in the Luger pistol. The 9x19mm Parabellum cartridge is a rimless, tapered pistol round that offers moderate recoil and good stopping power, making it suitable for military use. Its popularity and effectiveness have ensured its continuous usage in various firearms even to this day.