A Bar at the Folies-Bergère (French: Un bar aux Folies Bergère) is a painting by Édouard Manet, considered to be his last major work. It was painted in 1882 and exhibited at the Paris Salon of that year. It depicts a scene in the Folies Bergère nightclub in Paris. The painting originally belonged to the composer Emmanuel Chabrier, a close friend of Manet, and hung over his piano. It is now in the Courtauld Gallery in London.
https://en.wikipedia.org/wiki/A_Bar_at_the_Folies-Bergère
Édouard Manet (23 January 1832 – 30 April 1883) was a French modernist painter. He was one of the first 19th-century artists to paint modern life, as well as a pivotal figure in the transition from Realism to Impressionism.
On the one hand, it looks like there a mirror behind her, the clientele being reflected. But then that couple in diagonal from our point of view messes with that illusion, more so because the woman shown from behind is wearing the same dress, or at least similar cut but identical color, and hair.
Yah.
From https://mymodernmet.com/edouard-manet-bar-folies-bergere-painting/