sentences:  In 1967, Frantz and Claus Kanngießer won the second prize at the international music competition of the ARD playing as a cello and piano duo, marking the beginning of his international career.He first played with the Berlin Philharmonic Orchestra, conducted by Herbert von Karajan in 1970.In 1975, he played in his United States debut concert with the New York Philharmonic Orchestra conducted by Leonard Bernstein, who became his lifelong friend.