Speaking a day after Syria's main opposition announced its formal participation in peace negotiations in Geneva was on hold, Hollande said he was concerned that a ceasefire that has dramatically reduced fighting across Syria might not last.
"If the truce is broken, fighting will restart, and civilians will flee once again. There will be no hope," Hollande said after talks with Jordan's King Abdullah II.
"For Jordan, what's happening in Geneva is very important. The suspension of talks is worrying."
Hollande, who visited Cairo yesterday, has said that everything needed to be done in order to ensure the cessation of hostilities holds.
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He has been on a regional tour to countries affected by war, during which he announced 100 million euros ($113 million) to Lebanon to help with the mass influx of Syrians escaping violence.
In Jordan, home to more than 630,000 displaced Syrians, the president discussed the refugee crisis as well as the fight against the Islamic State group.
"There are still refugees coming from Syria after fleeing fighting around Raqa and Palmyra. We need to support them but also ensure that terrorism isn't brought with them," Hollande said.
Jordan, which is part of a US-led coalition battling IS in Syria and Iraq, has struggled to cope with the numbers of Syrians seeking refuge in the kingdom.