"It's quite symbolic, as marines we're the successors of the 177 men of the first marine commando battalion," added Artur, who gave only his first name under French military rules for speaking to the media.

But while the military honours the only French unit to make landfall on June 6, 1944, in the first step to liberating their country from Nazi occupation, current conflicts like Russia's invasion of Ukraine are also on their minds.

"This is a commemoration, but it's also a training exercise alongside our allies that allows us to plan and prepare together," said Major Johann.

He is in charge of planning landing operations from the vast below-decks command centre on the French amphibious assault ship Mistral, holding station off the Normandy coast.

"France is lucky to be one of the only countries to have this capability, not many countries can these days," Johann noted.

"We'll never reproduce the Second World War model" when more than 150,000 Allied troops landed in Normandy, he added.

"But we work with the resources we have now... being able to train alongside our allies brings us the mass that we're currently missing."

- 'Ship always ready' -

NATO soldiers are already thinking about how to adapt to the changes to modern battlefields on show in Ukraine, like the intense use of drones making it near-impossible to hide major troop movements.

"We're trying to make combat faster and more fluid, avoiding concentrating our forces in one landing spot but rather spreading them out, so as to reunite on an objective further inland later on," Johann said.

Artur, who leads "10 or so" of the soldiers who embark onto grey landing craft from the floating dock in the Mistral's lower decks, has "many more operators trained to use drones" small enough to fit in a backpack.

"We use them on every mission, whether it's fighting the drugs trade, to see what's going on on a ship before sending anyone aboard, and of course for scouting out beaches, to see if there's danger," the 26-year-old sergeant said.

Two sleek helicopter drones weighing 150 kilograms (330 pounds) each are also tucked into the Mistral's echoing hangar deck alongside far larger piloted transport and attack aircraft.

"They're useful for expanding the sensor 'bubble' around the ship," said the vessel's commander Captain Olivier Roussille.

But his main task remains "being able to deploy a combat company or even a brigade" from his 200-metre (670-foot), 22,000-tonne ship to shore.

In Normandy, the Mistral's job goes beyond memorial ceremonies and training, as its crew keep the proceedings and visiting dignitaries -- including French President Emmanuel Macron, US leader Joe Biden and Ukraine's Volodymyr Zelensky -- safe.

"Whatever's going on, a military ship is always ready," Roussille said, casting his eyes over the bridge with its constantly updating radar screens overlooking the flight deck loaded with Tiger attack helicopters.