Russia's foreign ministry said earlier on Friday that it intends to call a session of the United Nations Security Council to discuss the Turkish government's statements about a possible ground operation in Syria, Reuters reported.
"There is a risk of war between Turkey and Russia," Hollande told France Inter radio. "There is an escalation."
"Negotiations must resume, bombardments must stop, aid must come," he said.
Russian warplanes entered Syria's increasingly complex five-year-old conflict at the end of September, backing the forces of their ally Assad, and bombing rebel positions.
The Turkish military shot down a Russian jet in November it said had breached its airspace while on a bombing campaign in neighbouring Syria.
"There must be pressure on Moscow so that we have negotiations," Hollande said. "Moscow will not succeed by unilaterally backing Bashar al-Assad."
Hollande said in the radio interview that he had told Russian authorities: "You are not striking the right spots and you are striking civilian populations, which is unacceptable."
Turkey, opposed to the government in neighbouring Syria and worried about advances by Kurdish militants in Syrian territory, this week had to deny a media report that it had already sent troops over the border.
Turkish Foreign Minister Mevlut Cavusoglu also told Reuters this week that his country, Saudi Arabia and some European powers wanted ground troops in Syria, though no serious plan had been debated.
The Syrian government and its allies, including Russia, must cease hostilities on Friday in line with an agreement made between major powers on February 11, France's Foreign Ministry spokesman said earlier on Friday.
