Rather than sitting "properly" and posing to the viewer, the girl in the painting looks bored and tired, and the room around her is messy, indicating of Cassatt's tendency towards Realism.

Bourgeoisie
A new upper-middle class

Realism
Depicting contemporary life

Mary Cassatt, Little Girl in a Blue Armchair, 1878, oil on canvas, 89.5 x 129.8 cm, National Gallery of Art, Washington D.C.

Cassatt liked to depict the bourgeoisie and its new leisure activities such as going out to the Opera. Note the man across the hall who is using binoculars to observe the woman in the painting.

Haussmann
A new city landscape

Bourgeoisie
A new upper-middle class

Realism
Depicting contemporary life

Mary Cassatt, In the Loge, 1878, oil on canvas, 81.28 x 66.04 cm, Museum of Fine Arts, Boston.

Since women's status was still inferior to that of men, they were often barred from academic institutions. This led many women artists to stay home and portray domestic scenes.

Bourgeoisie
A new upper-middle class

Realism
Depicting contemporary life

Mary Cassatt, The Child's Bath, 1893, oil on canvas, 100.3 x 66.1 cm, Art Institute of Chicago.

Cassatt aimed to portray her surroundings as close to reality as possible, seen here through the bored look on the subjects' faces and the sense of coldness that exists between them.

Bourgeoisie
A new upper-middle class

Realism
Depicting contemporary life

En Plein Air
Painting outdoors

Mary Cassatt, A Woman and a Girl Driving, 1881, oil on canvas, 89.7 × 130.5 cm, Philadelphia Museum of Art, Philadelphia.