Notre-Dame’s Restoration: A Look at the Rebuilt Spire, Stained Glass, and Gargoyles

French President Emmanuel Macron recently conducted a televised tour of Paris’s Notre-Dame cathedral, offering the public its initial glimpse inside the edifice since much of it was devastated or damaged by a massive fire in 2019. From its spire to its stained glass, the structure has undergone a complete transformation. This effort goes beyond a mere post-fire renovation, representing a comprehensive overhaul that included the removal of decades of accumulated grime and soot since its last restoration. Here, we examine some of the key elements of the repair work and the methods employed. The spire’s collapse marked the most dramatic moment of the 2019 blaze. Many believed it to be a medieval component, but the original spire was actually dismantled in the 1790s due to safety concerns. Its successor, which was destroyed five years ago, had been erected decades later as part of a neo-Gothic reconstruction overseen by architect Eugène Viollet-Le-Duc. For the current reconstruction, carpenters utilized a blend of traditional techniques and computer-aided design to craft the substantial wooden base. This base was then hoisted into position by Europe’s largest crane, after which a scaffolding shell was erected to enable workers to assemble the progressively rising structure. Consistent with the rest of the roof, the spire is clad in lead. A new gilded cock now adorns its apex, replacing the original that fell during the fire. Although recovered, the original was too damaged for reuse. Within the new cock are sacred relics, including a thorn from the cathedral’s Crown of Thorns, and a parchment bearing the names of 2,000 individuals who contributed to the renovation. The most striking characteristic of the refurbished cathedral is the brightness of its stonework. This effect stems from the cleaning of all limestone blocks, with some sections also being replaced. Replacement stone was procured from quarries in northern France. Experts were able to identify minute features in the original stone, such as specific fossils, which aided in pinpointing its geographical origin. While the vast majority of the masonry remained intact, it was coated not only in centuries-old layers of dust and dirt but also in a film of soot and lead powder from the fire. Cleaning involved high-power vacuums, followed by a spray application that peeled away to remove the grime. In total, approximately 40,000 square metres of stone were cleaned. To reconstruct the vaulted ceiling beneath the former location of the spire, masons had to reacquaint themselves with the principles of Gothic architecture. This involved using a wooden frame to position the stones and culminating the structure with a keystone. The entire 100-meter wooden roof was consumed by the fire, with none of its 800-year-old timbers surviving. However, a swift decision was made to replace them as accurately as possible, using oak sourced from French forests. Fortuitously, an architect named Remi Fromont had previously conducted an in-depth study of the timber frame for his university thesis. This study proved invaluable, serving as a blueprint for the carpenters. Around 1,200 oak trees were required, with specific criteria: they needed to be straight, free from knots and a condition known as “frost-crack,” and 13 metres long. Much of the wood was hand-sawn and then shaped with axes, mirroring the methods used for beams in the 13th century. The building now incorporates 35 “fermes” (the triangular structures that bear the weight) along its entire length. Many of the exterior sculptures, including the renowned (though not medieval) gargoyles and chimaeras, suffered damage from the high-pressure hoses employed to combat the fire. Many were already in poor condition due to pollution. A dedicated workshop was established in front of the cathedral to repair and, where necessary, replace these statues. Five of the gargoyles, creations of Viollet-le-Duc’s imagination, were digitally scanned and subsequently remade in limestone. Inside the cathedral, prominent sculptures like The Virgin of the Pillar and The Vow of Louis XIII remained undamaged. Nevertheless, all have undergone cleaning and minor repairs. The cathedral’s numerous paintings have also been cleaned, including the “Mays”—large-scale depictions from the life of Christ that were an annual offering to the cathedral in the 17th Century from the goldsmiths of Paris. One of the most remarkable transformations within the cathedral is the re-emergence of color in the choir and many of the side-chapels. Here, too, the fire presented an opportunity to uncover the splendor hidden beneath decades of accumulated crud and soot. Hues of blue, red, and gold have reappeared, combining with the creamy tones of the revitalized limestone to create a sense of lightness that likely approximates the original aesthetic. A similar outcome is evident with the stained-glass windows. These were unharmed but heavily soiled. They were disassembled, removed, cleaned, and then reinstalled. The large rose-windows were left untouched. Again, much of what visitors observe today is not genuinely medieval but rather a product of Viollet-le-Duc’s medieval-inspired vision. The grand organ, constructed in the 18th Century, was unaffected by either heat or water during the night of the fire. Its challenge arose from the accumulation of a yellow dust, identified as lead monoxide, within its pipes. The entire instrument—standing 12 metres high, featuring six keyboards, 7,952 pipes, and 19 wind-chests—was dismantled and transported to workshops outside Paris. Sheep-leather linings were replaced, and new electronic controls were integrated. Following reinstallation, the organ underwent re-tuning, a process spanning several months as each pipe is meticulously adjusted. On 7 December, the Archbishop of Paris’s inaugural words upon entering the restored cathedral will be: “Awake oh organ, Let God’s praise be heard!” The eight bells of the north tower were also removed in 2023, a substantial undertaking given their size. They were cleaned and treated before being returned a few weeks ago. The largest of these bells is named Emmanuel. Visitors will also observe alterations to the cathedral’s liturgical arrangement, as its altar, lectern, and seating were all destroyed. A simple bronze altar has been fashioned, accompanied by new chalices for the sacraments. The congregation will find 1,500 new wooden chairs, and a new reliquary has been placed behind the choir to house the Crown of Thorns. Additionally, new vestments for the clergy have been designed by Jean-Charles de Castelbajac. The renovation efforts at Notre-Dame have provided a significant advantage for archaeologists, granting them access to subterranean areas that predate the cathedral’s construction by hundreds of years. Among the numerous bone sets unearthed are those believed to belong to the Renaissance poet Joachim du Bellay. Another significant find was the carefully interred remnants of the medieval rood-screen, which originally separated the sacred area of the church from the congregation. This 11-metre stone partition, erected in the 13th Century, featured rich and colorful sculptures depicting the life of Christ. It was dismantled in the 18th Century following a revision of church regulations. However, clergy evidently intended for these remains to be rediscovered, as the components appear to have been laid with considerable care beneath the ground. There is hope that they can be reassembled and put on public display. Despite the successful renovation, the work is not yet complete. Scaffolding remains around much of the eastern end, and in the coming years, the exterior walls of the apse and sacristy will require treatment. Furthermore, there are plans to redesign the esplanade and to establish a museum within the adjacent Hôtel-Dieu hospital.