​​​On the morning of 6 June 1944, the British 3rd Infantry Division landed in front of Hermanville-sur-Mer and Colleville-sur-Orne at 07:25. Within thirty mimuntes of that landing they were followed by No. 41 RM Commando who touched down at the western end of Hermanville.

​Their objective was to capture Lion-sur-mer before linking with No. 48 RM Commando, 4th Special Service Brigade, who had landed on Juno Beach. Upon landing, No. 41 RM Commando began to regroup and headed for a German fortified position code named ‘Trout’ by the Allies. This was Wiederstandnest, WN21, consisting of two 50mm anti-tank guns, mortars and machine guns.

​At the head of operations was Lieutenant-Colonel Gray who launched several assaults, but each one was unsuccessful. Without their radio equipment, all lost during the landing, the commandos could not communicate effectively to get fire support from the ships positioned offshore.

​The German forces counter attacked in the afternoon and held out stopping No.41 RM Commando. WN21 was finally taken the next day, with the support of navy destroyers. It was with the help of the 1st South Lancashire Regiment, 2nd Lincolnshire Regiment and 2nd Royal Ulster Rifles, that the Commandos succeeded in liberating Lion-sur-mer and the castle of Haut-Lion on 7 June. Some small pockets of German resistance at Rue du Maréchal Foch and Rue de la Hève held untill 9 June.

The British commandos paid a heavy price in liberating Lion-sur-Mer. In addition to the three officers killed or wounded on the beach, a Luftwaffe attack from German bombers caused the death of three new commandos and wounded nine others, including Gray himself.

One month later, several Lionnais, residents of Lion-sur-Mer, were also among the dead. 15 civilians (including the Mayor) had taken refuge in a rescue station. They were killed in their sleep, affected by a parachute mine dropped from a German bomber on 2 July at dawn.

To honour No.41 RM Commando, a plaque was fixed on Maritime Boulevard. A stele in memory of the Allied soldiers and civilian victims of 6 June 1944, and the square of 2 July 1944, recall the tragedies experienced by the inhabitants of Lion-sur-mer.