The Security Council unanimously decided on Monday, including Russia, which supports the regime of Syrian President Bashar al-Assad, to deploy UN observers in Aleppo to supervise evacuations and assess the situation of civilians.
The adoption of this resolution, proposed by France, marks the first sign of unity for months between the major world powers struggling with a conflict that has already made more than 310,000 dead since March 2011.
Russia had threatened to veto it.
The French resolution calls on UN Secretary-General Ban Ki-moon to rapidly deploy UN humanitarian personnel already present in Syria "for adequate, neutral and direct observation" of the evacuation of the parties Besieged Aleppo ".
With this "humanitarian resolution", France's objective is "to avoid a new Srebrenica", a city in Bosnia where the worst massacre in Europe since the Second World War was committed in 1995, the French ambassador to the United Nations, François Delattre.
It is still unclear whether the Syrian regime will allow access by UN observers to the ravaged city.
"This is a starting point," Delattre told reporters. "We will be extremely vigilant," he added.
Ban Ki-moon will have to inform the Council within five days if access has been authorised by the Syrian authorities, which have repeatedly blocked UN assistance in the past.
More than 5,000 people threatened by hunger and cold were able to leave Monday the besieged Aleppo rebel sector before the vote at the UN.
In total, since the beginning of Thursday of the evacuations of this district of the second city of Syria, at least 14,000 people, including 4,000 insurgents, were able to leave on board of buses towards other rebel zones in the north of the country, After the estimates of the Syrian Observatory for Human Rights (OSDH).