France says it will vote in favor of upgrading the Palestinian Authority's status at the United Nations from "observer" to "nonmember state."
The UN General Assembly is due to vote on the Palestinian request on November 29.
Foreign Minister Laurent Fabius told the lower house of parliament that "when the question is asked," France, which is a permanent member of the Security Council, "will vote yes."
The Palestinians are most likely to get a majority at the 193-member UN General Assembly but face opposition from the United States and Israel.
The Palestinian envoy to the United Nations, Ritad Mansour, said the vote "will be a historic event."
The Foreign Ministry of Israel said that the French decision "comes as no surprise."
Ministry spokesman Yigal Palmor warned that the chances for a resumption of peace talks after the General Assembly vote "will be even dimmer."
Palmor said the Palestinian move "is in fundamental breach with existing agreements," which reverses the order of "first negotiate, then reach an agreement, then get UN recognition." He said the bid was "detrimental to peace."
U.S. State Department spokeswoman Victoria Nuland, speaking at a news briefing in Washington, called the Palestinians' move "a mistake."
"We do not think that any move in the General Assembly is helpful or any text in the UN General Assembly is helpful," she said. "We think it's going to be, as I said yesterday, a mistake."
Robert Serry, the UN envoy for the Middle East peace process, speaking during his monthly briefing to the UN Security Council, urged the General Assembly to vote responsibly.
"A Palestinian state is long overdue and is key to addressing the legitimate aspirations of both peoples and paramount to the stability of the region," Serry said. "[UN Secretary-General Ban Ki-moon] hopes that all concerned look at the consequences of any decision they make responsibly."
British UN ambassador Mark Lyall Grant said Britain has not yet decided how to vote.
On November 26, the leader of the Islamist movement Hamas, Khaled Mishaal, told Palestinian Authority President Mahmud Abbas that it is also backing its UN bid.
Hamas's move is seen as the latest sign of rapprochement between the Palestinian political rivals. Hamas had previously opposed the move, since it implies indirect recognition of Israel.
Abbas controls the West Bank, while Hamas governs the Gaza Strip, where militants fought an eight-day conflict with Israel that ended last week with a cease-fire. Some 160 Palestinians and six Israelis were killed.
Based on reporting by AP, AFP, and Reuters