After the party what did Madame Loisel not want the other woman to see?

Madame Loisel did not want the other woman to see her coat.

He threw over her shoulders the clothes he had brought for her to go outside in, the modest clothes of an ordinary life, whose poverty contrasted sharply with the elegance of the ball dress. She felt this and wanted to run away, so she wouldn't be noticed by the other women who were wrapping themselves in expensive furs.