​​Dunkirk was one of the last major strongholds still controlled by German forces in northern France. Under the command of Admiral Friedrich Frisius, a garrison of 6,000 troops—including 2,000 SS soldiers—held the city, determined to resist at all costs. To hinder the advancing Allied forces, the Germans had flooded the surrounding Moëres marshlands as early as February 1944 and forcibly evacuated civilians, particularly the elderly and children.

​As Canadian troops and the French Forces of the Interior (FFI) closed in on the city in September 1944, the Dunkirk pocket gradually shrank. The Allies liberated Bourbourg and Gravelines on 7 September, Loon-Plage on 9 September, and La Panne in Belgium on 10 September. However, progress was slow due to the difficult terrain and the strong German defenses. Despite the worsening situation for the German troops, acts of violence by the occupying forces continued. On 6 September, six captured FFI members were executed at Fort des Dunes in Leffrinckoucke. Later, on 16 September, retreating German forces detonated explosives in Bergues, killing 42 civilians.

​The Canadians initially planned a full-scale assault on Dunkirk but abandoned the idea due to the city's formidable defenses and the need for reinforcements in the Netherlands. Instead, only Canadian artillery remained in position, while the 4th Special Service Brigade took over. This unit was later replaced by the Czechoslovak Independent Armoured Brigade under General Alois Liška, supported by French resistance fighters.

​In early October 1944, a temporary 60-hour truce allowed 18,000 civilians—whom the Germans referred to as "useless mouths"—to flee the besieged city. However, German forces, following Frisius’ orders, continued to resist. The siege of Dunkirk dragged on through the winter, with heavy casualties on both sides. It was only on 8 May 1945, the day of Germany’s surrender, that Frisius finally received the order to cease fighting. The next day, he negotiated the terms of surrender with General Liška, agreeing to lay down arms, evacuate the city, and release military and civilian prisoners.

​Dunkirk was the last town in the region to be liberated. The battle left significant destruction, with thousands of mines left by retreating German forces. In the aftermath, the French army took charge of securing the city while British forces detained Frisius. The prolonged siege resulted in 117 Allied deaths, 26 missing soldiers, and over 240 severely wounded.​