Unfortunately, the French had to pull almost all of the ground forces that had much combat value out of North Africa and into the fight for metropolitan France in Weygand's attempt to hold a line after Dunkirk. They would have had to get forces back to Africa in order to hold out there.
I've toyed with a "French Hold Out in North Africa" scenario a few times, and it is difficult to make work. For one thing, any major weapons system that they get to North Africa (planes, tanks) quickly loses value because of lack of spare parts. They would have to rely on British and US production for anything beyond small arms.
Evacuation of ground forces runs into the problem that the French were barely holding the line in France to begin with. Moving substantial forces out of the line for evacuation would have hastened the collapse, and forces slated for evacuation might not have beaten the Germans to the ports of southern France. They could have called up the next class of potential inductees, or at least the ones in the part of France they still held, and sent them to North Africa to be trained and equipped, but raw recruits like that would be of little military value for six months or more. It would have been tough to make holding out there work, especially since the French would have had to worry about not just Italy but also Spain trying to grab pieces of French territory, plus the prospect of Arab revolts.