Between 6,000 and 6,500 Roma were interned in 31 camps in France under the Vichy regime.
President Francois Hollande acknowledged Saturday France's "broad responsibility" for the internment of thousands of Roma by the World War II Vichy regime and in the early months of the post-war government.
"The day has come, and this truth must be told," Hollande said on the first presidential visit to the main internment camp for Roma, located in Montreuil-Bellay, central France.
"The (French) Republic acknowledges the suffering of travelling people who were interned and admits that it bears broad responsibility," he said.
Roma, also known as gypsies, were brutally persecuted in the Holocaust, in parallel with the systematic murder of Jews. Estimates of how many died vary widely, between 220,000 and half a million.
Between 6,000 and 6,500 Roma were interned in 31 camps in France under the Vichy regime, the government set up in France -- but under de-facto Nazi control -- after France surrendered to Germany in 1940.
The regime fell in the wake of the June 1944 Allied invasion of Normandy and General Charles de Gaulle set up a provisional government.
The biggest of the Roma internment camps was Montreuil-Bellay, where more than 2,000 were confined between November 1941 and January 1945. About a hundred of them died.
The camp was also used to intern a number of homeless people from the city of Nantes. Some Roma remained interned in French camps until 1946.
"Nearly all families of travelling people have at least one relative who passed through Montreuil-Bellay," Hollande said.
"A country, in this case ours, is always bigger for recognising its own history," he said.
Survivors and descendants of the victims were among a crowd of more than 500 people who attended Saturday's ceremonies, held some seven decades after the last interned Roma were freed.
"It was important for us to have this recognition. It affects thousands and thousands" of Roma families, said Fernande Delage, head of the France Liberte Voyage NGO.
"It's late, but better late than never," he added.
Lucien Violet, a 69-year-old whose parents were held in Montreuil-Bellay, also attended the ceremony.
"This is the first president to pay homage to travelling people. We feel genuinely moved by his presence," he said.
"Our families have suffered enormously and we will never forget, even though there is forgiveness."
For many, returning to the site of the camp threw up difficult memories.
"It hurts, it really hurts to come back here," admitted another survivor called Henriette Deschelotte.
"We did what we could but we were very unhappy," she said.
Sandrine Renaire, who heads the Friends of Montreuil-Bellay gypsy camp (AMCT), said her family were terrified of leaving the nearby town of Saumur for they would be rounded up.
They "never left Saumur out of fear of being caught on the roads and locked up", she said.
"They were deprived of their freedom, which is the worst thing that could have happened to them."
At the site, a commemorative installation has been set up. Created by ceramics artist Armelle Benoit, it consists of a portico of eight columns engraved with the names of the 473 affected families.
At the ceremony, Hollande threw his weight behind parliamentary moves to scrap a 1969 law that defenders of minorities say is discriminatory.
The legislation traces its roots to a 1912 regulation which sought to push Roma to settle down by requiring "nomads" to have special ID cards.
In 1940, the law was changed, ostensibly as a result of the war, requiring travellers to have a fixed address in a move which Hollande said was "the result of distrust fed by ancestral fears, prejudices and ignorance".
Three decades later, it was replaced in 1969 by the requirement for "travelling people" to have a specific set of papers and name a district as their home base -- legislation which the parliament is now likely to repeal.
"It will be, I hope, settled by the parliament so that travelling people no longer have to carry this booklet, so that they can be citizens just like everyone else," Hollande said.