In Guy de Maupassant's short story "The Necklace", the character of Madame Forestier is a great example of a static character. A static character is defined in literature as a minor participant of the plot who, regardless of what role it takes in the story, does not become affected by any of the situations to the point of actually changing.
In not so many words, a static character is just "there" and really does not change nor influence the story at all. Madame Forestier is clearly a minor character. She simply lends Madame Loisel the fake diamond necklace that the latter believes to be real and then pays for after she lost it. Madame Forestier is simply a friend of the main character who facilitated the her with an object. The object may have changed the main character, but not Madame Forestier. The loss of the object, even, did not change a Forestier, who simply missed it casually. However, the loss of the necklace changed Madame. Loisel's life forever.
Therefore, if you analyze Madame Loisel and how she changed in the story you can clearly see how Madame. Forestier would be a static character in comparison.