Paris, like Washington and London, would also consider any use of chemical weapons by Syrian President Bashar Assad as a legitimate justification for direct military action, even without a U.N. Security Council resolution, Hollande told French ambassadors in his first annual foreign policy speech.
"With our partners we remain very vigilant regarding preventing the use of chemical weapons, which for the international community would be a legitimate reason for direct intervention," he said.
Syria has said it would use such weapons only in the event of an external attack.
Hollande urged Syria's divided opposition, whose members have differed on how to end Assad's rule, to agree on an approach and then unite as a provisional government.
"France asks the Syrian opposition to form a provisional government -- inclusive and representative -- that can become the legitimate representative of the new Syria," Hollande said.
"France will recognize the provisional government of Syria once it is formed," he said.
His remarks were the strongest words yet by a Western leader to push Syria's often squabbling opposition groupings toward unity, The New York Times said.
They also revealed possible French differences with other Western countries, British newspaper The Guardian said. Washington and London have been more guarded in their dealings with Syrian opposition groups, including the Syrian National Council coalition based in Istanbul, Turkey.
While Washington and London have distanced themselves from the SNC, seeking closer ties with internal rebel elements, France has remained a strong backer, The Guardian said.
Hollande said France would include "our Arab partners to accelerate" a provisional Syrian government's creation.
He did not say what partners he meant or if he had an agreement with any of them.
The Arab League is trying to encourage opposition factions to sign up to a common transition plan for a post-Assad Syria, but the SNC has been reluctant to take part, fearing a dilution of its influence, The Guardian said.
Hollande also confirmed France and other Western countries were working with Turkey on possibly establishing "buffer zones" inside Syria.
"We are working ... [on] the initiative of buffer zones proposed by Turkey," Hollande said. "We are doing so in coordination with our closest partners."
Washington had no immediate comment.
When Turkey proposed buffer zones -- whose official purpose would be to protect refugees -- it said it did not want its own forces to invade Syria and create such zones.
Hollande additionally criticized Russia and China in his remarks for vetoing Security Council resolutions on Syria. Their "attitude is weakening our capacity to ensure the United Nations Charter is respected," he said.