What is an example of irony in the story "The Necklace" by Guy de Maupassant?

"The Necklace" by Guy de Maupassant is an ironic story in the sense that Mathilde Loisel was ultimately brought down by what she wanted most in life — expensive things. Mathilde was a pretty girl who was raised in a modest family, but she always wanted to be rich. Even when she married a clerk, she still desired riches out of her reach. One day, Mathilde's husband brought her an invitation to a lavish party, but Mathilde did not want to go because she did not think she owned anything enough to wear to the party. Her husband encouraged her to wear her best ball gown, but she did not think it was good enough. She went to Madame Forrestier and borrowed one of her best necklaces for the party. Mathilde loved the necklace and the attention it brought her at the party; she finally had the fame she always coveted. It was not until after the party that Mathilde realized she lost the necklace. In a panic, Mathilde and her husband went to a jeweler to attempt to replace the necklace. An exact replica would cost 36000 francs, far more than the humble clerk's salary. The couple borrowed money at usurious rates. Mathilde worked as a maid to help pay off the loans. The couple did this for ten years. After ten years, Mathilde ran into Madame Forrestier again. Madame Forrestier commented that Mathilde looked terrible, and Mathilde explained she lost Madame Forrestier's necklace and bought her another one to replace it. At that point, Madame Forrestier told Mathilde the necklace was a piece of costume jewelry made of paste that cost less than 400 francs. This is the irony of the situation. Mathilde coveted fame and riches her entire life, but was miserable when she got it. The jewelry she borrowed thinking it was worth so much was something she could have easily bought in a novelty shop.  
https://americanliterature.com/author/guy-de-maupassant/short-story/the-necklace