"France firmly condemns the increasingly brutal repression in Syria, including the use of heavy weapons, as in Jisr al-Shughur, from where many civilians are fleeing into Turkey," the foreign ministry said in a statement.
"This unacceptable situation, which makes the toll of civilian victims in Syria still heavier, threatens regional stability. It should end," it said.
"Syrian authorities should give the International Committee of the Red Cross and other humanitarian agencies immediate access," it added.
"France is continuing its efforts with its partners in the international community to encourage the United Nations Security Council to live up to its responsibilities by reacting without delay to the Syrian crisis and its regional implications."
Earlier, Syrian state media had said the regime's forces were battling what it described as "armed gangs" in the northwestern town of Jisr al-Shughur.
Rights activists cited reports of heavy shelling and strikes by helicopter gunships.