Hidden in a Paris chapel's walls: bones from the cemetery of 500 guillotine victims

In 2018, tiny cameras pushed through the mortar joints of a Paris chapel revealed four sealed chambers packed with earth and human bones. The building is the Chapelle Expiatoire, raised on the old Madeleine cemetery, where about 500 people executed by guillotine on today's Place de la Concorde were buried during the French Revolution, together with Louis XVI and Marie Antoinette.

The cemetery opened in 1722 as a modest parish burial ground on Rue d'Anjou. On 30 May 1770, Paris staged a fireworks show on Place Louis XV to celebrate the wedding of the future Louis XVI and the Austrian archduchess Marie Antoinette. A deadly crush followed in the narrow Rue Royale. Officials counted 132 victims, and the Centre des monuments nationaux says 133 bodies were laid out and buried at the Madeleine.

Twenty-three years later, the same ground received the couple themselves. Louis XVI was guillotined on 21 January 1793 and Marie Antoinette on 16 October 1793. Each was put in a coffin in a separate pit and covered with quicklime. The cemetery also received other victims of the Terror, including Charlotte Corday, Olympe de Gouges, Madame du Barry, Manon Roland and Philippe Égalité, the king's cousin who had voted for his execution. Overwhelmed, the cemetery was closed on 24 March 1794.

A neighbor, Pierre-Louis Olivier-Desclozeaux, bought the plot in 1802 and claimed to have identified the royal graves. After the monarchy returned, he sold it to Louis XVIII. On 21 January 1815, the 22nd anniversary of the king's death, the royal remains were taken to the Basilica of Saint-Denis and the first stone of a memorial chapel was laid. Architect Pierre Fontaine built it from 1816 to 1826.

Louis XVIII gave one striking order: no earth "saturated with victims" was to leave the site. While digging the foundations, Fontaine reported "a prodigious number of bones" and wrote that they were gathered and sealed in four vaults in front of officials. Then the trail went cold. For generations, people assumed the Madeleine dead had been moved to the Paris Catacombs, where a plaque does name a Madeleine cemetery. The chapel's administrator, Aymeric Peniguet de Stoutz, noticed that the plaque's address points to a different parish burial ground.

He also saw that the lower chapel, designed as an open space, had walls built between its pillars, and a heating plan drawn in 1853 showed empty spaces behind them. Rather than break into a listed monument, forensic anthropologist Philippe Charlier slid endoscopic cameras through the joints between the stones. Behind all four walls, the images showed tall wooden chests, probably lined with leather, holding soil and human bones. Charlier told Le Figaro he could make out ribs, long bones, a radius and a fibula.

These are not neat skeletons but earth mixed with bone fragments, likely including ordinary parishioners and the 1770 crush victims. No individual has been identified. Even so, a monument built to atone for a king's execution turned out to be a resting place for hundreds of people killed by the Revolution, including a man who had voted for it.

The chapel survived its own political storms. In May 1871 the Paris Commune ordered its demolition, and Jacques Libman stalled the work by posing as a rich American buyer until the Commune fell. About twenty more demolition proposals followed before the building was listed as a historic monument in 1914. Its lower chapel still holds a black marble altar placed where Louis XVI's body was exhumed.

Sources: Centre des monuments nationaux: history of the Chapelle Expiatoire; Centre des monuments nationaux: the rediscovery of the ossuaries; Historia: interview with Aymeric Peniguet de Stoutz; Le Figaro (2018): interview with Philippe Charlier; RFI (2020); L'Histoire: the Rue Royale disaster of 1770; Britannica: Philippe Égalité. Cover: Chapelle Expiatoire and its white rose garden, Paris, by Thomon.