Original: Ertl was born in Stuttgart, Germany where he would later study physics from 1955 to 1957 at the Technical University of Stuttgart and then at the University of Paris (1957-1958) and Ludwig Maximilians University in Munich (1958-1959).
Simplified: He studied at the University of Paris from 1957 to 1958 and then at Ludwig Maximillians University in Munich from 1958 to 1959. He returned to the Technical University of Stuttgart where he got a diplom of physics in 1961.