The outdoor Ambassadeurs, where Edward joins the other Murers, was famous for more than its lights among the trees. Singers, comedians, and acrobats performed. The female singers who were its most important stars were handsomely costumed, their repertoire often more popular than refined. You can see the crowd in the general admission seats on the left. In the novel, the Murers sit at one of the tables available at a higher charge. Carl dismisses the pretty girls sitting on the stage as unable to hold a girl at the Renicks' party, but you can see them for yourself here and here.