The fall of the "Falaise pocket" was the final blow in the Battle of Normandy.

The Falaise pocket or battle of the Falaise pocket (German: Kessel von Falaise; 12--21 August 1944) was the decisive engagement of the Battle of Normandy in the Second World War. Allied forces formed a pocket around Falaise, Calvados, in which German Army Group B, consisting of the 7th Army and the Fifth Panzer Army (formerly Panzergruppe West), were encircled by the Western Allies. The battle resulted in the destruction of most of Army Group B west of the Seine, which opened the way to Paris and the Franco-German border.

Here's a short film about "The Fall of Falaise" from 1944.