The disparity between social classes in 19th-century France is a key theme in A Simple Heart. Félicité is resoundingly working class and spends her life selling her labor to middle-class employers who seek to exploit her as much as possible. This relationship of class exploitation is written into the first line of the story, which reveals the envy of Madame Aubain’s middle-class friends that she should be able to employ such a competent maid servant for such a consistently low wage.

Félicité’s vulnerability to such exploitation demonstrates the relationship between class and agency. Though Madame Aubain is left with significant debts after the death of her husband, she can sell properties and other assets that support her and her family. Even at her lowest point, Madame Aubain owns two properties and employs a maid, whereas Félicité never has this kind of financial safety net. Similarly, Théodore can use his financial resources to avoid the military draft, an option that would not be available to working-class men. His wealth allows him to dictate the course of his life, while working-class characters such as Félicité are subject to the whims of others—a point his abandonment of her underscores.