The Clock Tower stands on the site where the ancient tower that served as the Arengario of the People appears to have stood, and takes its current form between the late 15th and early 16th centuries. In 1480, the clock face was decorated with the Este coats of arms and those of the Community by Francesco Bianchi Ferrari. In 1508, the octagonal dome at the top of the tower was erected, based on a design by Bartolomeo Bonascia, and in 1520 the balustrade that crowns the quadrangular structure was built. In 1730, a new clock, the work of Ludovico Riva, was installed, while in 1868 Ludovico Gavioli designed the one that still stands in the palace today, with two dials: one in Piazza Grande and the other in Piazzetta delle Ova, a full 40 meters away but operating with the same mechanism.

In 1761, Domenico Puttini built the marble balustrade that surrounds the Immaculate's balcony: the statue of the Virgin was placed there in 1805. Another statue of the Madonna with Child and St. John the Baptist, a terracotta work by Antonio Begarelli now preserved at the Civic Art Museum in Modena, had previously adorned the facade of the palace.