Character Analysis
The mayor of Verrières is a pretty straightforward guy. He likes status and he likes money. In fact, that narrator criticizes him early in the book for measuring the value of everything in dollars and cents. When questioned about why he cuts his trees so thinly, the mayor answers,
"I love shade, and I have my trees cut so they provide shade, nor can I conceive of any other use for trees, especially when, unlike the useful walnut, they bring in no revenue." (1.2.6)
In other words, he says, he can do whatever he wants with his private property, and the only reason he doesn't rip the trees down completely is because he can't sell them for good money.
As you can imagine, the mayor doesn't like it when he hears chatter around Verrières about how his wife is sleeping with his children's peasant tutor, Julien Sorel. Monsieur de Rênal likes Julien, but he likes his own sense of pride even more. He says at one point,
"Why should I let [my wife], and her lover, laugh at me as if I were a nobody, some barefoot beggar? Should everyone in Verrières be gloating about how good-natured I am?" (1.21.17)
In other words, Monsieur isn't a totally mean guy. He wants people to like him… but he wants people to respect him even more.
Monsieur de Rênal's Timeline