On 1 August, as most of the German Panzer (tank) divisions attempted to halt the advance of the 1st Canadian Army and 12th British Corps near Caen, France, the U.S. 21st Army Group mounted a major offensive. General Patton's U.S. 3rd Army drove to the south while General Hodges' U.S. 1st Army moved to the east. On 6 August, the German 7th and 5th Panzer armies launched a counteroffensive against the U.S. 1st Army, driving it back. However, once the German attack had been held, the Allied forces were in a position to encircle the two Panzer armies. On 7 August, as the U.S. 12th Army group advanced from the southwest, the 1st Canadian Army moved east from Caen with the 12th British Corps. The German armies attempted to avoid the trap, and a savage struggle ensued around the French town of Falaise.
The 1st Canadian Army was responsible for the northern sector of the gap. The 4th Canadian and 1st Polish Armoured divisions together with the 2nd and 3rd Canadian Infantry divisions and the 51st British (Highland) Division doggedly fought their way forward. By 16 August, the 2nd Canadian Division had taken Falaise, and, by 17 August, the 1st Canadian Army had advanced another 10 miles (16 kilometres) attempting to close the gap by linking with the Americans. On 18 August, the 2nd SS Panzer Corps counterattacked north of the town of Chambois, but the 4th Canadian Armoured Brigade and 1st Polish Division held their positions. The following day, the 3rd and 4th Canadian Infantry divisions linked up with the 90th U.S. Division at Chambois, completing the encirclement of the German forces.
On 20 August, the trapped German forces made a desperate effort to break out of the encirclement through Chambois, but the 3rd and 4th Canadian divisions repulsed every German attempt. Although many of the troops of the 7th and 5th Panzer armies managed to escape, they abandoned most of their equipment and vehicles. The last days of fighting were ferocious. Indeed, elements of the Canadian and Polish divisions were cut off and desperately short of supplies until the gap was definitively closed on 21 August. Major David Currie, commanding the Sherman tanks of "C" Squadron of The South Alberta Regiment and infantry of The Argyll and Sutherland Highlanders of Canada and The Lincoln and Welland Regiment, was awarded the Victoria Cross for his actions in this final phase of the battle. Five days later, the Allies entered Paris.