Speaking at the former slaving port of Goree Island, Senegal, the French junior minister for cooperation said the country must face up to the fact that it and other European countries profited from the trade in African slaves to Europe and the Americas.
On Wednesday, Brigitte Girardin said: "Together we must reflect, with courage and clarity, on the past - yes, France, as well as other European countries, definitely profited from the trade in humans.
"Today, like in the past, the greatness of a country lies in its readiness to recognise the darkest moments of its history," she said at a ceremony attended by Abdoulaye Wade, the Senegalese president.
Over the course of three centuries until 1848, thousands of Africans passed through Goree Island's "Gate of No Return", just off the former French colony's capital, Dakar, to board slaving ships, mostly headed to the Americas.
In all, estimates suggest between 11 and 12 million slaves were shipped from Africa by European slavers.
Girardin said: "For the first time in its history, France is contemplating and remembering the unbearable and undeniable stain that slavery is on the history of humanity."
"The greatness of a country lies in its readiness to recognise the darkest moments of its history"
French junior minister for cooperation
France has chosen May 10 to commemorate the abolition of slavery as it was on that date five years ago that Paris adopted a law recognising the trade as a crime against humanity.
France was the first country in the world to do so.
Senegal's Wade said the suffering of Africa's slaves could not be measured or compensated in monetary terms.
"There are some things that have no price," Wade said.
France first abolished slavery in 1794, but it was reinstated by national hero Napoleon Bonaparte in 1802 before it was definitively abolished in 1848.