I did some geneological checking and didn't find any direct French ancestors for Deas. According to Ancestry.com Deas' background was as follows:

Deas' parents were Col. James Sutherland Deas (b. 5/24/1784, d. 11/19/1864 Mobile Co. AL) and Margaret Rebecca Chestnut (b. 1/24/1786 Camden, SC, d. 11/3/1874 Mobile Co, AL).

James Sutherland Deas' parents were John Deas and Elizaeth Allen.

John Deas' parents were David Deas and Catherine Dundas.

David Deas' parents were Henry Deas and Rebecca Key.

Probably the French connection is Deas' schooling in France and, as you said, the greater awareness of history at the time.

Ryan