I found "something" from a book titled "Recherches généalogiques sur les familles Gravel Cloutier, Bruneau, Defresne, Proulx, Douville, Charest, Buisson, Tessier, De Lessard, Caron, Morin, Lamothe, Lemaitre,..." by Desaulniers, François Lesieur, 1850-1913. But it's only hearsay. A canon from Dinan met Mgr. Elphège Gravel who was then staying in Rome, and told him there were Gravels in Dinan including Joseph Gravel who had come from Illiers and married Marguerite Macé... and then Mgr Gravel told that story to someone, etc.
I believe Dinan (Côtes-d'Armor) has a few registers which go back as far of the early 16th century so it could be worth a check.