Guy de Maupassant, a Norman himself, served as a a soldier in the Franco-Prussian War as a young man and was first exposed to the pettiness of the Norman peasants, a pettiness which appalled him. This story is a social criticism of these people. Through the character development of old Maitre of Breaute (a title used for shopkeepers and farmers), Maupassant portrays the results of the ingrained-suspicion and envy of the Norman peasants.
Thus, the theme of his short story "The Piece of String" involves the development of how deception born of one's petty pride can be one's undoing among those of the same ilk. Maitre Hauchecorne's efforts to conceal his miserly act of bending down for a meager piece of string lest he be ridiculed by the inhabitants of Goderville leads to his mendacious and exaggerated protests of having done anything wrong. When, for instance, he is told by the mayor of Goderville that another shopkeeper Monsieur Malandain, a rival of his, observed him as he bent down for "the pocketbook lost by Maitre Houlbreque, of Manneville," Hauchecorne flushes with anger and deprecates Malandain, actions which lead the mayor to discredit Hauchecorne's proof of the piece of string as what he retrieved. The mayor is unconvinced, especially in light of the fact that Hauchecorne tried to distinguish his ridiculously frugal act by "searching in the mud for some time." Here Hauchecorne's petty nature turns upon himself:
He went home, feeling humiliated and indignant...especially crushed because, as a shrewd Norman, he knew himself capable of doing what he was accused of, and even boasting about it as a good trick.
In his too exuberant protests, Hauchecorne fuels the suspicious nature of the other peasants, and he is completely discredited.
"Ha! With such an explanation, he must be lying!" they said behind his back. He sensed this, ate his heart out, and exhausted his strength in useless efforts. He visibly began to weaken.
Hauchecorne's initial deception and petty nature works against him, especially with those of the same nature as he. As Sir Walter Scott's famous words "Oh, what a tangled web we weave when first we practice to deceive" can be amended to add "especially among other deceivers." Clearly, the petty and suspicious nature of the Norman peasants is at the heart of the narrative of Maupassant, who once declared,
Everyone is perfidious, a liar and a phony. Everyone wears a false face.
I have never heard of a story titled "The Pieces of String" by Edgar Allan Poe. I believe you have it confused with a famous short story by the French writer Guy De Maupassant. Consequently I have changed your topic accordingly. In Maupassant's story a very poor and frugal man is falsely accused of finding a valuable piece of jewelry because he was seen picking up a piece of string and mistakenly believed by one village gossip to have been picking up the lost jewelry. The gossip spread all over the village and ruined the poor man's life. The theme of Maupassant's story was that people can cause a lot of harm to others through meanness and slander. You can learn a great deal more about Maupassant's story by checking with eNotes' references via the links below.