“ A younger brother, Émile (1857–1906) , became an assistant in the print-room at the Bibliothèque Nationale, and afterwards joined the staff at the Musée du Louvre, of which he eventually became keeper, retiring in 1902. He was a well-known connoisseur of art. ”

“ He died on the 19th of May 1904, after a short illness, leaving in manuscript a criticism on the sources of the Speculum historiale of Vincent de Beauvais.
His elder brother, Charles (b. 1843) , is also of some importance as an historian, particularly on the history of art and on the heresies of the middle ages. He was appointed professor of history at the university of Toulouse in 1886. ”