"I want ... a clear condemnation of these crimes in a resolution from the UN Security Council... that places the perpetrators under sanctions," Ayrault said in a statement on Sunday after a UN experts' report said the Syrian army had attacked a village with chemical weapons in 2015. The Islamic State group has also been accused of using mustard gas as a weapon.
"The Syrian army and Daesh have used chemical weapons against civilians on at least three occasions," Ayrault said, using an Arabic acronym for IS. "These acts are inhuman and unacceptable."
He called on UN Security Council members to "assume their responsibilities".
France, the US and Britain have repeatedly called for sanctions over the use of chemical weapons, especially against President Bashar al-Assad's government.
But Assad's ally Russia, a permanent Security Council member, has cast doubt on the UN experts' findings, claiming that they are not sufficiently conclusive to warrant sanctions.
The row over Russia's role in Syria led to President Vladimir Putin calling off a visit to Paris this month.
Heavy clashes erupted on Sunday morning between regime and rebel forces in the divided city of Aleppo after a "humanitarian" ceasefire announced by government ally Russia expired before the UN could evacuate wounded civilians from rebel-held areas.