The hostages, who were freed on Tuesday, arrived at the Villacoublay military airport at about midday to be met by Hollande, who hailed their courage faced with "so many trials, so much waiting, so much suffering".
Meanwhile, media reports claimed that money had been paid to free them.
France's external intelligence service handed "more than 20 million euros" to the negotiators who obtained the hostages' release, a "French source acquainted with the details of the operation" told Le Monde newspaper on Wednesday, as the four headed home from Niger.
There was earlier speculation that the men's employer, partly state-owned power company Areva, might have paid a ransom, thus keeping within the letter, if not the spirt, of the president's declaration but Le Monde says the money came from the secret service's own funds.
Negotiations to free the four men - Pierre Legrand, Daniel Larribe, Thierry Dol and Marc Féret - dragged on for months and were caught up in rivalry between different wings of the French state, reports say.
The team that finally freed them was led by security contractor Pierre-Antoine Lorenzi, a former civil servant, and Mohaled Akotey, an adviser to Niger's Presideent Mahamadou Issoufou.
They apparently left for north-west Mali eight days ago, accompanied by 16 other men, both French and Tuaregs from the region.
The hostages had been split up to avoid a French military operation to free them and the negotiators arranged for them to be brought together in one place, whose situation was revealed when the money was handed over.
Hollande opposed the payment of ransoms on the grounds that it was an incitement to armed groups to kidnap other French nationals and there are charges that Islamist groups in north Africa had used former ransom payments to buy arms, some of which sould have been used to fight the French in northern Mali this year.
But the hostages' families and friends mounted a campaign to get the four freed, increasing political pressure on Hollande and his government.
At least seven other French citizens are being held hostage after being snatched in Mali, Nigeria and Syria.
The French presidency insisted on Wednesday that the country does not pay ransoms.