Since the flight is a 767, they would also have to open a CLT 767 International crew base and then pay to train CLT 767 crews to do international operations. That would cost significantly more than the $80 Schengen (not French) visa.
And, since the press release says the service is seasonal, what would they do with all those internationally trained pilots in the winter? Pay them extra to fly domestic trips (when they already have sufficient crews to cover the domestic schedule?)
It makes no sense at all to train CLT crews for international operations for ONE SEASONAL city pair.