The sets of the ballet were designed by French film and theater director René Allio.
Like so many of the other past productions of Notre dame de Paris, Allio took the more symbolic representation of the cathedral. You know it’s Notre Dame you’re looking at but it’s not an accurate depiction. It’s depicted as brown with details in paint messy looking lines. It looks like a fresco trying to look like stained glass. Like Notre Dame broke into piece and clumsy put back together. Which is apt as that was Hugo description of Quasimodo.
Other than the Notre Dame de Paris edifice set, the other set that is most noteworthy is the bell tower. At the start of the second act, Quasimodo climbs down the set as the bell rings.
While you’re not always going to play attention to the sets they work for the ballet’s mood, tone and add to its overall very unique style.