The newspaper said it had obtained a copy of the report, due to be submitted to UN Security Council members on March 26.
"After carefully avoiding to use the word 'independence' during 14 months of sensitive negotiations, Ahtisaari concludes in his final report that 'independence under international supervision is the only viable solution,'" Le Monde said.
According to the extracts published by Le Monde, "the maintenance of the international administration in Kosovo is not tenable" and "the reintegration of Kosovo into Serbia is not a viable option."
Ahtisaari is opposed to a continuation of political ambiguity, saying that it poses a threat to peace and stability in Kosovo, and stressing that independence is the only guarantee against that risk, the newspaper said.