Having been born into the upper class but raised in the middle class, Guy de Maupassant is the perfect author to write about middle class materialism during the Second Empire in France. De Maupassant's short story is a protestation against the materialistic mindset.
The Second Empire began under Napoleon III in 1852, about the time de Maupassant was born, and lasted until 1870, brought to an end by the Franco-Prussian War, which de Maupassant served in. Just as modernization brought wealth to all nations, modernization also helped France increase in wealth during this time period, inspiring the lower classes to become much more materialistic (Kelly, M., 1992, "Materialism in Nineteenth-century France," French Literature, Thought and Culture in the Nineteenth Century).
In de Maupassant's short story, Mathilde is characterized as materialistic because she is unhappy with her middle class surroundings and instead longs for expensive furnishings, multiple course meals, clothes, and jewels, feeling that "she was made for them" (p. 2). Her intense, obsessive desire for material possessions leads her to induce her husband to give her all of his 400 francs in savings so she can buy a new dress to wear to a ball. Her materialism further leads her to ask to borrow what she believes is a real diamond necklace from a wealthy friend to wear with the dress. Yet, instead of Mathilde being made happy by these possessions, she is made even more miserable. When Mathilde loses the necklace, she and her husband must move to an impoverished garret flat and work endlessly to pay off the debts they acquired to replace what they thought was a real necklace. The result is that, while at the start of the story she saw herself as poor and miserable in comparison to the upper class though she truly wasn't, by the end of the story, she has fallen into the lowest state of poverty possible, all because of her materialistic desires.
Through having Mathilde fall into such a dire state of poverty, de Maupassant shows the dangers of a materialistic mindset.