I have found the original spelling of both Daragon and Darragon in records in France as far back as the 1500s.
In Canada I found the surname spelled Daragon, Darragon, Daragon-dit-Lafrance, D'Aragon, Deragon and mispelled Dragon.
In the USA I found all the above plus DeRagon and many descendants of Francois and Marie as simply Lafrance.
Good researching, Arlene DeRagon