In 1857, the year of publication, Flaubert's Madame Bovary was banned on grounds of overt sexuality. There was even a trial. Presiding over the trial, Imperial Advocate Ernest Pinard accuses the author of sexual corruption arguing that there is, "No gauze for him, no veils--he gives us nature in all her nudity and crudity."
Underneath the sexual excuses, the charges likely also stemmed from the depiction of a woman who expresses her frustration with the traditional roles of women. Flaubert recognized the stifling and discontent women suffered in his time. His character Emma, the protagonist, tries in her desperate way to break free.
To the patriarchal establishment, Emma is the epitome of the "bad girl." Emma has two affairs. She is a wretched mother. She wracks up debt. She has big dreams.
In the beginning of the tale, she is married to Charles. Charles is a doctor, and makes a decent living. He is a kind but dull man. Bored out of her mind, Emma has her first fling. One of Charles's patients has hosts a ball, and Emma becomes enchanted by the world of true wealth. Her desire for passion and money is what instigates her two affairs.
After the first failed affair with Léon Dupuis, Emma meets Rodolphe Boulanger, who at least recognizes Emma's frustration (of her, Boluanger says, "(S)he’s gaping for love like a carp on the kitchen table for water.”) But for him, the affair is nothing more than a few days of excitement. Boluanger is more interested in the secret of their affair than anything else. When rumors begin that they are being found out, he becomes disenchanted.
For a while, Emma tries to mend her ways. She shows more interest in her daughter and her life. However, she still longs for more. She and Boulanger reinvigorate their affair. Her spending gets out of control, so much so that it threatens to ruin her husband, Charles. Emma convinces Boulanger to run away with her to Italy. He agrees, but then changes his mind.
Emma is devastated. She sees no way out and no hope for the future. She ingests arsenic and dies. Later, Charles finds her love letters to Boulanger. Rather than blaming Emma, Charles thinks it is fate. Charles dies as well, presumably of a broken heart.
What is scandalous about all of this, beyond the details of Emma's breaking of all of society's rules for proper behavior for women, is the fact that Emma is never sorry for what she has done. She never asks for forgiveness, she does not regret using her body to achieve her goals. Even today, some readers feel that Emma is a unlikeable character who "gets what she deserves" but Flaubert knew that women had little choice other than to use their bodies as commerce when they had no other way to achieve any measure of freedom. Flaubert once said that "Woman is a vulgar animal from whom man has created an excessively beautiful ideal." By vulgar he means human, with base wants and needs just like men; they cannot possibly live up to the "excessively beautiful ideas" about them which patriarchy has imposed. Emma is more victim than villain.