Edgar Degas, 1874. Behind-the-scenes ballet rehearsal. Musée d'Orsay.
From Wikipedia
The Ballet Class is an oil painting on canvas created between 1874 and 1876 by the French artist Edgar Degas. The painting depicts a group of ballet dancers at the end of a lesson, led by ballet master Jules Perrot. Known for portraying dancers, Degas captured the grace and the rigorous nature of ballet as a profession. The Ballet Class is housed in the Musée d'Orsay, Paris, France. It was commissioned by the composer Jean-Baptiste Faure. The Ballet Class closely resembles The Dance Class, also painted by Degas in 1874.