“Why and where were we dropping leaflets in France? Didn’t we control 99% of it?”
Good question. Maybe there were besieged holdouts that were urged to give up. The 8th Air Force diary where this entry originated doesn’t say.
http://www.8thafhs.org/combat1944b.htm
Your source says “Mission 673: 9 aircraft drop leaflets in France, the Netherlands and Germany during the night.” which makes more sense. In that context it was probably more of a generalization of the area between the french/german border.