From Ailes 10/1945,
here is a DS.10, a low-wing light monoplane Project as I suggest,created by J. Durandeaux,
in the book; Les Avions Francais 1944-1964,he designed a light aircraft called D.510,or
maybe it was a misprint and they meant DS.10 and they saw the letter "S" as the number
"5" ?!.