The Germans, realizing this, began building fortifications around these ports earlier in the war through their Organization Todt, as part of the Atlantic Wall concept.

Cherbourg, at the tip of the Cotentin Peninsula in Normandy, was captured by the Americans who landed on Utah Beach, but the German garrison destroyed its harbour facilities before surrendering.

Soon after, the Germans in the Brittany peninsula were isolated by a north–south breakthrough accomplished by George S. Patton's Third United States Army, exploiting the success of Operation Cobra.

The US VIII Corps was diverted into Brittany to capture Brest and secure the northern flank of the breakthrough and to prevent German reinforcements to Army Group B and threatening the Falaise pocket as well as fortifying the defenses of the French capital of Paris.

The old fortress city of Saint-Malo was captured by the 83rd Infantry Division ("Ohio") on 17 August, but its small port facilities were sabotaged by the defenders.

A German garrison stationed at nearby Cézembre Island surrendered only after days of heavy shelling by warships and strong air strikes, when their naval guns were already disabled.

It was clear that the Germans would deny the Allies the use of French ports as long as possible by defending the fortresses built around them and severely damaging their docks.

The fight proved extremely difficult, as the German garrison was well entrenched and partially made up of Fallschirmjäger (paratrooper) forces as well as Kriegsmarine personnel ranging from U-boat and E-Boat crews to battleship sailors, including those who were survivors rescued from damaged or sunk vessels, Naval Infantry of the Marine Stosstrupp Kompanie, and soldiers of disbanded Luftwaffe Field Division sent to reinforce the Normandy coast.

Whilst some less capable units surrendered quite easily, the Fallschirmjäger defended their ground under considerable odds, heavy shelling, air strikes and American assaults.

The Germans had stocked a considerable amount of ammunition for the defense of the city and had weapons of all calibers (from light flak to naval guns) dug into fortifications and in pillboxes.

When U.S. Brigadier General Charles Canham arrived to accept Ramcke's surrender, the latter asked the lower-ranking man to show his credentials.

After the war, the West German government paid reparations to civilians in Brest who had been killed, starved, or left homeless.