quality:corruption
Bells

Notre-Dame currently has ten bells. The two largest bells, Emmanuel and Marie, are mounted in the south tower. The eight others; Gabriel, Anne Geneviève, Denis, Marcel, Étienne, Benoît-Joseph, Maurice, and Jean-Marie; are mounted in the north tower. In addition to accompanying regular activities at the cathedral, the bells have also rung to commemorate events of national and international significance, such as the armistice of 11 November 1918, the liberation of Paris, the fall of the Berlin Wall, and the September 11 attacks.

The bells are made with bronze for its resonance and resistance to corrosion. During the medieval period, they were often founded on the grounds of the cathedral so they would not need to be transported long distances. According to tradition, the bishop of Paris held a ceremony in which he blessed and baptized the bells, and a godparent formally bestowed a name on the bell. Most of the cathedral's early bells were named after the person who donated them, but they were also named after biblical figures, saints, bishops, and others.

After the baptism, the bells were hoisted into the towers through circular openings in the vaulted ceilings and mounted to headstocks to allow the bells to swing. Notre-Dame's bells swing on a straight swinging axis, meaning the axis of rotation is just above the crown of the bell. This style of ringing produces a clearer tone, as the clapper strikes the bell on the upswing, called a flying clapper. However, it also causes great horizontal forces, which can be up to one and a half times the weight of the bell. For this reason the bells are mounted within wooden belfries which are recessed from the towers' stone walls. These absorb the horizontal forces and prevent the bells from damaging the relatively brittle stonework. The current belfries date to the 19th-century restoration.

Before the French Revolution, it was common for the bells to break, and they were often removed for repairs or to be entirely recast, and sometimes renamed. The bell Guillaume, for example, was renamed three times and recast no less than five times between 1230 and 1770.

The practice of bell-ringing at Notre-Dame is recorded as early as 1198. By the end of the 14th century the bells were marking the civil hours, and in 1472 they began to call to prayer for the Angelus three times a day, both practices which continue today. During the French Revolution, most of the cathedral's bells were removed and melted down. While many of them bore the names of the medieval bells, most were relatively recent recastings made from most of the same metal. During the 19th-century restoration, four new bells were made for the north tower. These were replaced in 2012 with nine as part of the cathedral's 850th anniversary celebration.

In addition to the main bells, the cathedral has also had smaller secondary bells. These included a carillon in the medieval flèche, three clock bells on the north transept in the 18th century, and six bells added in the 19th century – three in the reconstructed flèche and three within the roof to be heard in the sanctuary. These were destroyed during the 2019 fire.