"A ceasefire has been announced. It must be fully respected and the sooner, the better," Hollande told reporters yesterday during a visit to Peru.
He said the four Western powers would join forces to push for "discussions on a real political transition" in Syria.
All four countries called for an end to the humanitarian crisis in Syria and urged the regime of President Bashar al-Assad to cooperate in the aid effort for those affected.
"It is high time for this, otherwise refugees will continue to come and there will be an unbearable humanitarian situation in Turkey," one of Syria's neighbors where countless refugees have fled.
More From This Section
Hundreds of thousands of refugees fleeing fighting in Syria have risked their lives trying to reach Europe.
Syria's regime agreed yesterday to the ceasefire deal announced a day earlier by the United States and Russia, aimed at halting its nearly five-year civil war.
There were widespread doubts about whether the truce could take effect by the weekend as hoped.
The agreement does not apply to jihadists such as the Islamic State group and Al-Nusra Front, putting up major hurdles to how it can be implemented on Syria's complex battlefield.
The deal calls for a "cessation of hostilities" between forces loyal to Assad and opposition groups that would take effect at 2000 GMT Friday.