Australia's newest museum — a tribute to the men and women of World War I — has been opened in France by Prime Minister Malcolm Turnbull.

So much of the background about the conception and creation of the Sir John Monash Centre has been written, there seemed little left to say or do apart from unveiling the plaque.

How unexpected, then, for French Prime Minister Edouard Philippe to deliver words so beautiful and evocative they forced a collective intake of breath.

He spoke for what seemed like just minutes, but hearts momentarily stopped and eyes welled up.

"I could not help thinking of the terrible loneliness which these thousands of young Australians must have felt as their young lives were cut short in a foreign country," Mr Philippe said.

"A foreign country. A faraway country. A cold country whose earth had neither the colour nor texture of their native bush."

He spoke in French with English subtitles on a screen behind him racing to keep up with his words.

It did not matter that the vast majority in the crowd did not speak his language.

Simply reading his speech was powerful enough to bring people to tears.

Colonel Scott Clingan (left) escorts Edouard Philippe, Malcolm Turnbull and Lucy Turnbull at the military cemetery. ( AP: Pascal Rossignol )

In this region where Australia and its allies are hailed as saviours, Mr Philippe began his speech with the words of a German, written by another German — in the famous war novel All Quiet on the Western Front.

"He is entirely alone now with his little life of 19 years, and cries because it leaves him," he said.

Millions from both sides of the war witnessed horrors. But it is the Australians for whom the French feel so much debt.

Mr Philippe paid tribute to the Australian soldiers who defended the French land they held inch-by-inch, "as if it were their own country".

"And it is their own country," he said.

"For many young Australians, this earth was their final safe place.

"For many of them, this earth was the final confidante of a thought or a word intended for a loved one from the other side of the world.

"Loved ones who would only learn the sad news several months later."

Edouard Philippe and Malcolm Turnbull unveil a plaque at the Sir John Centre Australian National Memorial. ( AP: Michel Spingler )

Mr Philippe, who became France's Prime Minister with the election of President Emmanuel Macron, is a keen student of history and spoke about moments in the battles around Villers-Bretonneux that resonated with him.

"We cannot relive these stories," he said.

"The mud, the rats, the lice, the gas, the shellfire, the fallen comrades — we can never truly imagine what it was like.

"So we must tell them. We must show them — again and again.

"Show the faces of these young men whose lives were snuffed out in the mud of the trenches.

"Show the daily lives of these 20-year-old volunteers from far away who listened only to their youthful courage, to their love for their country, or that of their parents or grandparents, to die here in Villers-Bretonneux.

"Show it with the help of modern technology, without taking our eyes off the names etched onto the memorial — names which are real, not virtual.

"We will never forget that 100 years ago, a young and brave nation on the other side of the world made history by writing our history.

"Lest we forget."