Complex sentence: He taught at the Schola Cantorum in Paris starting in 1956, and at the Académie international d'été de Nice starting in 1959 and was a professor at the Paris Conservatoire from 1967 to 1988.
Split into simpler sentences: He taught at the Schola Cantorum in Paris starting in 1956, and at the Nice International Academy starting in 1959. He was a professor at the Paris Conservatoire from 1967 to 1988.