What is the subject of the necklace?

The subject of "The Necklace" by Guy de Maupassant is the consequences of vanity and greed. It follows the story of a woman named Mathilde Loisel who borrows a necklace to wear to a fancy ball, only to lose it and spiral into debt to replace it. Ultimately, she discovers the necklace was a fake, leading to a tragic realization about the consequences of her desire for wealth and status.