Some of the monuments have had their day. I remember as a child finding around the house a book entitled something like The Hundred Greatest Novels. Eaach was summarized in quite some detail. Most were long and turgid books from the 19th century. Flaubert's Salammbo was one I remember. Another was Eugene Sue's Wandering Jew. I doubt that many of them are considered great by experts today.
Oh, I wouldn't have expected Sue's "Wandering Jew" to be in such a list !
I read it as a teen-ager and had found it very entertaining, as well as "Les mystères de Paris", but as other Sue books, it's a strange mix of melodrama and politics (just in the middle of sad stories of abandoned young women, orphans or starving works, wham, long paragraphes against death penalty or reforms of jails or independence of women...) If I remember correctly, most of his books were banned by the Catholic church for decades (well, the villain in "The Wandering Jew" is a Jesuit monk who is absolutely devilish, and kills dozens of people in order to finally become the head of the Jesuits and then the pope...)
I've never even tried "Salammbo"...
I had to read two Zola books when I was in junior high school and high school ("Germinal", which I unfortunately studied twice at school, and "La Curée") and I disliked it enough so that I never tried another one. I don't have a fond memory of Balzac's "La Peau de chagrin" (studied at school too) and admit I read almost nothing else from him.
On the other hand, I really loved "Great expectations", "David Copperfield", "Oliver Twist", "A tale of two cities" and "Hard times" when I read it as a teen-ager (but have started at least three times "Martin Chuzzlewit" later and never finished it...)