"Coming to this house you get the feeling of a fighter, a combatant, a militant who lived here among his own," said Hollande after spending time at the matchbox brick building, which is now a national monument.
Accompanied by South African President Jacob Zuma, Hollande spent the morning in the formerly blacks-only area southwest of Johannesburg, which was a hotbed for resistance against the white supremacist apartheid regime.
They also visited a memorial to Hector Pieterson, a 13-year-old schoolboy shot dead by police in 1976 when school children protested being taught in Afrikaans, the language of Dutch descendants.
Dozens were killed by police during the protest.
"It is very moving to come to Soweto, where hardly 40 years ago children died defending their freedom, their dignity," said Hollande on the second day of a state visit to South Africa.
"All this isn't so long ago," he said, adding that "the battle for human dignity, for equality, for respect and tolerance... these battles live on even long after the heroes who waged them."
Tuesday marked the 20th anniversary of Mandela being awarded the Nobel Peace Prize jointly with then-president FW de Klerk for negotiating an end to apartheid.
Mandela went on to become the country's first black president after all-race elections in 1994.
The ailing 95-year-old receives few visitors these days besides close relatives. Discharged from hospital after a three-month stint, the critically ill former statesman is being treated at his Johannesburg home.
Hollande was due to meet Mandela's wife Graca Machel later in the day.
The small single-storey house where Mandela lived from 1946 to 1965 in Soweto was the centre of his political activity prior to his arrest.
After his imprisonment, his then wife Winnie stayed behind, becoming a strong anti-apartheid beacon in her own right.
The couple divorced in 1992.