The 94-year-old former POW accompanied French Prime Minister Edouard Philippe on Saturday to the remote valley where the bloody battle raged for 56 days before France’s shock defeat that would pave the way for the communist nation's independence.
"This is like being in a dream, I'm thinking of my comrades, of all my men," said Allaire, who was captured by communist soldiers in 1954 and held for more than seven months, includin a 90-day "death march" to a prison near the Chinese border.
As the fate of the French became clear in March 1954, he received a written order from his commander: "Cease combat and destroy your weapons".
He kept the note throughout his captivity and carried a copy of it in his jacket pocket to the battle site Saturday, an area he called "unrecognisable".
"It was a small village, far from everything (in 1954). Today it's a city, which proves that Viet Minh fighters didn't fight for nothing," he said.
The ferocious battle in the rugged, remote valley killed 13,000 people on both sides in under two months, as Vietnamese fighters hemmed in French forces -- equipped with superior weapons -- and bombarded them with heavy artillery.
Vietnam's win over the French led to the country's division into the communist-ruled north, headed by revolutionary leader Ho Chi Minh, and a pro-US southern regime.
That set the stage for two decades of war which would end with unification and America's defeat in the Vietnam War in 1975.
Today France is one of Vietnam's most important allies, with soaring trade worth $7.6 billion and cosying military alliances.
Philippe, who is in Vietnam for a three-day visit until Sunday, is the second senior French leader to visit Dien Bien Phu after President Francois Mitterrand in 1993.
"It is difficult to imagine that for several month this was the site of intense fighting rarely seen," Philippe said, after touring France's former underground command centre and lighting incense at a memorial plaque.
"For those who lived through those moments, I know the emotion is very intense and once again the message that I want to convey here, is a message of admiration, of respect and of pride," he said.
'No more hatred'
Ahead of the visit, several Vietnamese veterans recalled the fight-to-the-death spirit that carried them to victory, despite the odds the faced.
Hoang Bao was barely 20 years old when he trekked hundreds of kilometres to the site, facing off with the French full of hate and ready to die for his country's independence.
But today, retired colonel Bao is happy to call his former foe a friend.
"We have no hatred toward the French any more," the 85-year-old told said in Hanoi, wearing his dark green military uniform decorated with medals.
But he said there are important lessons to be learned to avoid the mistakes of the past.
"The French didn't learn our history well, so they lost... Vietnam is different from other countries, we are not willing to surrender," he said.
Facing the French in battle was complicated for some fighters like Bao, whose lives were closely intertwined with their colonial rulers, sometimes going to school or working alongside them.
But driven by patriotism and a fierce thirst for independence, many Vietnamese took up the struggle fortified by bitter memories of invasion by the Chinese, Japanese and French.
They were also buoyed by Communist slogans that urged everyone to pitch into the war effort.