What happened in the "D-Day of the South", when southern France was invaded from the sea?
Code named Operation Dragoon, the little-known landings in southern France took place in mid-August 1944, over two months after the landings in Normandy. The idea was two-fold: 1) The German defenses would have been weakened by the shift of troops and armor north to fight the original landings, so the invasion would be easier and 2) that it would drain German resources from other fronts, and perhaps enable the main invasion in the north to breakout and head for the German border.
Over 100,000 Allied troops were involved in the first day's landings, and in no small part due to a major attack by the French resistance and British commandos, they met little resistance. The British had argued against the plan rather strongly, thinking the Allies should concentrate on the fight in Italy and not shift soldiers and materiel from that front, but they were overruled by Eisenhower, who was the Supreme Allied Commander.