French Foreign Minister Jean-Yves Le Drian has said that the country had an "indication" that a chemical attack had been carried out in Syria's northeastern Idlib province this month as alleged by Washington last week.
"We have an indication that chemical weapons were used in the Idlib region, but for now it has not been verified," Le Drian told a parliamentary commission on Tuesday.
"We're being cautious because we consider that chemical weapons use has to be proven and be lethal, in which case we can react," he said.
President Emmanuel Macron has made use of chemical weapons by the Syrian regime a "red line" that would trigger a military reprisal against Bashar al-Assad.
The United States has also threatened reprisals if the suspected Idlib attack is proven.
International inspectors say that Assad's forces have carried out a series of chemical attacks in the course of the brutal civil war, which has killed more than 370,000 people and displaced millions since 2011.
A sarin gas attack in April 2017 in the town of Khan Sheikhoun killed 83 people, according to the United Nations, leading US President Donald Trump to order a strike by 59 cruise missiles on a Syrian air base.
And France joined Britain and the US in launching missile strikes on three suspected chemical weapons sites in Syria in April 2018 after a suspected chemical attack in Douma.
