The story is narrated in the first-person by Doctor Horace Bianchon. A young married society woman, Madame de Listomère briefly meets Eugène de Rastignac at a social gathering. The next day he writes a letter to his lover, Madame de Nucingen, but mistakenly addresses it to Madame de Listomère. When Madame de Listomère reads this letter she is scandalised. Rastignac only realises his mistake four days later, and it is confirmed to him by his friend, Horace Bianchon, who saw him writing the letter when he was visiting him.

Rastignac visits Madame de Listomère to try to clear the mistake. He is initially told that Madame is not home, but is let in by her husband when he arrives. Rastignac discovers that Madame de Listomère actually is at home and speaks to her. By this time, she has become convinced that he is genuinely attracted to her, but he tells her that the letter was actually for Madame de Nucingen. Rastignac leaves feeling embarrassed. For the next few days Madame de Listomère does not attend any social events, and Bianchon closes the story saying that he has been treating her for a slight attack of nerves, which she has been using as an excuse to stay home.

Despite being 18 pages long, Balzac paints a quirky and intriguing picture of romantic endeavors in 1800's Paris. Apart from describing women with detail (“her eyes, far from being dulled like those of so many Parisian women, have a gentle glow which becomes quite magical if, by chance, she is animated.”), he also makes social commentary on their position (“when she herself will be thirty-six years of age,—a period of life when most women discover that they are the dupes of social laws.”) 

Sparsely written, but a brief, comic and engaging read.