"The Miller's Tale" in The Canterbury Tales by Chaucer has four core characters: the carpenter, Alison, Nicholas, and Absalom. This is important to add here because they are all connected through their sexual desires. The carpenter, John, is married to Alison, who is eighteen years old and intensely beautiful. Nicholas is a student who is renting one of the carpenter's extra rooms, which is how he meets Alison and develops a strong desire for her—a desire which eventually becomes mutual. Absalom is the parish clerk, who is also madly in love with the beautiful Alison, and this is certainly not mutual. The only love, or at least desire, that seems shared is that between Alison and Nicholas.
That being said, Chaucer demonstrates the tension and superiority between different classes with the characters of John and Nicholas. When discussing with Alison how to trick John so that the two lovers can spend a night together, Nicholas says,
"Nay ther-of care thee noght," quod Nicholas,
"A clerk had litherly biset his whyle,
But-if he coude a carpenter bigyle." ("The Miller's Tale," lines 112–114)
What this means is that after all of his years studying, Nicholas is positive that he can devise a plan to trick the simple-minded carpenter. This demonstrates Nicholas's perceived superiority compared to the carpenter, because he is, or will be, university-educated. Therefore, in "The Miller's Tale," a solid example of Chaucer examining the intersection of sexual desire and social class is through the love triangle of the carpenter, Alison, and Nicholas.