From the years 1916 to 1918, Nadia Boulanger invited Moyse to play at her classes on musical analysis. Moyse was principal flute soloist in Paris's Opéra Comique and simultaneously, in order to prove himself, applied for the solo flute position at the Paris Opera. Although offered the position, he turned it down as it would interfere with his frequent visits home to St. Amour. Moyse's career continued to flourish, and he became first flutist with the orchestra of the Orchestre de la Société des Concerts du Conservatoire.