In August 1914 , after the start of World War I , Ponticelli joined the 1st RÃ giment de Marche of the French Foreign Legion at 16 years old . In August 1914 , shortly after the outbreak of World War I , Ponticelli joined the 1st RÃ giment de Marche of the French Foreign Legion at 16 years old , lying about his age to do so .