Duke of Montmorency
His paternal grandparents were Napoléon Louis, III. duc de Talleyrand-Périgord (1811-1898) and Anne Louise Charlotte Alix de Montmorency (1810-1858). His paternal great-grandparents were Alexandre de Talleyrand-Périgord, Duke of Dino (1787–1872) and later duc de Talleyrand-Périgord, and Dorothea of Courland, Duchess of Sagan (1793–1862). Another great-grandfather was the Duke of Montmorency.