"A Simple Heart" is all about social classes. Need proof? Flaubert mentions the bourgeoisie (the French middle class) in the very first sentence. And Félicité, the protagonist maid, is the representative of the lower classes. Her mistreatment is justified by the fact that she was born into a lower social class; it's just the way it is.
The story focuses a lot on dates, spanning the course of about fifty years. It was during this same timeframe that the July Revolution went down. If your French history is a little rusty, the July Revolution happened when one unpopular king was overthrown in favor of another, Louis-Philippe. L.P. was all about the middle classes (the bourgeoisie), and they had lots of power during his reign. Which means that people like Félicité didn't.
Questions About Society and Class
How does class factor into Félicité's first, failed love affair?
Why do all the bourgeois ladies envy Madame Aubaine?
What's the deal with all of Madame Aubain's family losing their land?
How does the story fit with themes of French history?
Chew on This
"A Simple Heart" shows that early-19th-century France was in need of a democratic revolution, to end class discrimination.
The characters in "A Simple Heart" discriminate against Félicité because she is of a lower class.