In “The Necklace” we have a third person omniscient narrator who focuses mainly on Mathilde. By focusing on Mathilde, the author Maupassant takes advantage of irony because we do not know what is really going on, only what she perceives. He also makes the story more suspenseful, because we do not know what is going on until the end.
The narrator is not without judgment, however. Consider how Mathilde is introduced to readers.
The girl was one of those pretty and charming young creatures who sometimes are born, as if by a slip of fate, into a family of clerks. (enotes etext pdf, p. 1)
We already are given a sense of foreboding from here. Mathilde is charming and young and beautiful, but she is doomed because of her social standing.
When Mathilde convinces her husband to go to the fancy party with her, she has to borrow a jewel from a friend of higher status. She chose a “superb diamond necklace, and her heart throbbed with an immoderate desire” (p. 3).
Her hands trembled as she took it. She fastened it round her throat, outside her high-necked waist, and was lost in ecstasy at her reflection in the mirror. (p. 3)
Although the narrator is omniscient, we do not know that the necklace she borrowed is a fake until the end of the story. We find out when she does. This increases the suspense and really drives home the irony.