Madame Losiel, husband of Monsieur Losiel believes she is poor and wants a better social life. One night her husband brings a invitation to the Minister's Court Ball.
Madame Losiel protests that she does not have a good enough dress for the Ball. Her husband supplies her with the money for a dress, and persuades her to borrow jewelry from her friend.
Madame Losiel takes part in the Minister's Court Ball, and was known to be the most beautiful women there.
When they return home from the ball, Madame Losiel realizes she lost her friend's necklace. Her husband searches all night for the necklace, but with no luck.
Madame Losiel and her husband decide to buy a replacement necklace, spending all their money on it including debt and spend ten years repaying the debt. They moved into a attic and Madame Losiel became a normal housewife. And poor.
One day Madame Losiel went on a walk through the part. She ran into her friend and told her the story of how they lost the necklace and had to replace it. Her friend simply said that it was made of paste and was a fake.