I had never associated the blue and white flag carried by the Alabama units of Wither's Division with a French background, but it does seem possible. As you mention, southern Alabama had a French history, being originally established by Pierre Le Moyne d'Iberville (born in Montreal, but he really got around).

According to the Wikipedia entry under "French Ensigns" - "in 1661 the use of white flags on merchant ships is explicitly forbidden, pointing the merchants instead to the "old flag of the French nation", which then was supposed to be a white cross on blue, with on it the royal arms." This may have been, or at least so understood by Deas to have been, the flag used by the first French settlers on the Gulf coast.

Incidently, Quebec's present provincial flag has a blue field surmounted by a white cross.

Ryan Toews