"This is more than a copy, it's a work of art!" said French President Francois Hollande as he visited the centre in Montignac, the village at the foot of the hills where the original cave complex is located.
The new project dubbed "Lascaux 4", which opens to the public on Thursday, aims to recreate the sensations experienced by the four teenage boys who found the cave on September 12, 1940.
The last of the boys still alive is Simon Coencas, now 89, who was a special guest at Saturday's event.
With World War II raging and the Nazis already in Paris, a friend of Coencas had enlisted him and the other boys to explore a hole in the ground in the hills above their village that his dog had found a few days earlier.
One of the boys carved out a space with his knife so they could get into the cave and continue their search by the light of a paraffin lamp.
"With my pals, we climbed down to explore a hole, we advanced bit by bit and at some point we came up upon the chamber of the bulls," Coencas previously told AFP.
It was with the lamp that they first saw the paintings: horses, bulls and deer jumping out of the cave walls.
The spectacular prehistoric art is thought to be 18,000 years old and has been on UNESCO's list of world heritage sites since 1979.
'We were hoping to find a treasure'
But tourists have been kept away from the original site since 1963 because the carbon dioxide they exhaled was damaging the paintings, wreaking havoc with the cave's fragile ecosystem.
And the early work preparing the site for visitors had also disturbed its environment more than the authorities anticipated.
"Lascaux 2", an earlier copy of the site, opened in 1983, but it reproduced only 90 percent of the cave's wall art, while "Lascaux 3" is a travelling exhibition showing highlights from the site.
The new version marks "the first time that we've reconstructed the entire Lascaux cave", said Jean-Pierre Chadelle, an archaeologist working with the Dordogne regional authority.
"Lascaux 4" took a team of 30 workers four years to complete at a cost of 66 million euros .
Housed in a half-buried building of concrete and glass, it replicates the dimensions, the artwork and colours of the original cave.
Coencas told AFP he still has fond memories of the games he and his friends played hunting for treasure on the Lascaux hill.
"We were hoping to find a treasure. We found one, but not the one we thought we would," he said.