The call comes after the Syrian army and its allies retook a large swathe of eastern Aleppo on Monday, prompting thousands of civilians to flee their homes
France on Tuesday called for an "immediate" UN Security Council meeting on Aleppo to tackle the "humanitarian disaster" in the besieged Syrian city.
"More than ever, there is an urgent need for a cessation of hostilities and unhindered access to humanitarian assistance", Foreign Minister Jean-Marc Ayrault said in a statement on Aleppo, where tens of thousands of civilians are trapped in the fighting between government troops and rebels.
A French diplomatic source added that Ayrault and his German counterpart would discuss Aleppo with Russian foreign minister Sergei Lavrov on the sidelines of a meeting in Minsk on Tuesday, at which leading European foreign ministers will discuss plans for implementing a ceasefire agreement for eastern Ukraine.
The Syrian army and its allies announced the capture of a large swathe of eastern Aleppo from rebels on Monday in an accelerating attack that threatens to crush the opposition in its most important urban stronghold.
Capturing eastern Aleppo would be the biggest victory for President Bashar al-Assad since the start of the uprising against him in 2011, restoring his control over the whole city apart from a Kurdish-held area that has not fought against him.
For Assad, taking back Aleppo would shore up his grip over the main population centers of western Syria where he and his allies have focused their firepower while much of the rest of the country remains outside their control.
France, a key backer of the Syrian opposition, is due to convene a meeting of countries opposed to Assad, including the United States, Saudi Arabia and Turkey, in December.
Dire humanitarian situation
The call comes after the Syrian government's advance prompted an exodus of thousands of desperate civilians, some fleeing to districts held by the government or Kurdish forces, others heading south into areas still under opposition control.
"The situation is disastrous," said Ibrahim Abu Al-Leith, a spokesman for the White Helmets rescue group in the Ansari neighbourhood.
"There is mass displacement and morale is in the gutter," he said, his voice cracking with emotion.
"People are sleeping in the streets. They don't have anything to eat or drink, but neither do we," he told AFP.
Syria's White Helmets warned on Monday they had no more fuel reserves for rescue vehicles.
In a video statement, the group urged "all humanitarian, aid, and medical organisations to immediately intervene to put an end to the humanitarian disaster" facing civilians in besieged Aleppo.