From The Montreal Museum of Fine Arts:
Edgar Degas found much of his inspiration in the world of ballet, theatre and café-concerts, focusing on the performers both on stage and in the wings. This canvas is one of the few in which Degas makes the audience, whether in the stalls, the pit or the boxes, his subject. It is an intimate close-up of a seamstress, absorbed in the show. Degas seems touched by her look of concentration. Unlike his predecessors, Honoré Daumier being an example, he does not make her a caricature.