Karl Wilhelm Naundorff sued the Bourbons as the lost son of Louis XVI, and DNA from the boy's heart ended the claim in 2000

Louis-Charles, son of Louis XVI and Marie Antoinette, died in the Temple prison in Paris on 8 June 1795, aged 10. At the autopsy the physician Philippe-Jean Pelletan took his heart. Royalists doubted the death, and after 1814 about 100 men claimed to be him. The most persistent was Karl Wilhelm Naundorff, a Prussian watchmaker, who said another child had been put in his place. On 12 June 1836 he sued Charles X and the Duchess of Angoulême, the dauphin's sister, for his inheritance. Three days later police arrested him, seized his 202-document dossier and expelled him to England. He died at Delft on 10 August 1845. His Dutch death certificate named him Charles-Louis de Bourbon, Duke of Normandy, and his tombstone reads "Here lies Louis XVII, King of France." His descendants used the name de Bourbon, granted in the Netherlands, and petitioned French courts and legislatures through the 19th and 20th centuries, with lawsuits in 1851 and 1874^†. René Charles de Bourbon lost a claim in a French court in 1954. In 1998 teams at Leuven and Nantes compared mitochondrial DNA from Naundorff's hair and a humerus with Marie Antoinette's maternal relatives and found no match. In 2000 tests matched the heart Pelletan had kept to that family. On 8 June 2004 the heart was placed in the Basilica of Saint-Denis. In 2026 some descendants still press the claim.