Complex sentence: Jennie Tourel made her operatic debut at the Opéra Russe in Paris in 1931, and made her debut at the Metropolitan Opera in New York in May 1937, as Mignon.
Split into simpler sentences: Jennie Tourel made her operatic debut at the Opéra Russe in Paris in 1931. Then she made her debut at the Metropolitan Opera in New York in May 1937, as Mignon.