L. L. Zamenhof
Duviard was a brother-in-law of Carlo Bourlet (1866–1913), who died at age 47, and whose "immense merit" was acknowledged by L. L. Zamenhof, the father of Esperanto. Bourlet's wife, Thérèse Marie Adam (1872–1923), was the sister of Duviard's first wife Elisabeth Antoinette Adam.