When he was 17 he went to Paris and had private organ lessons with Charles Tournemire . He became Tournemireâ s assistant at the Basilique Ste-Clotilde , Paris until 1927 . At age 17 , upon moving to Paris , he took private organ lessons with Charles Tournemire , whom he assisted at Basilique Ste-Clotilde , Paris until 1927 .