France's foreign ministry has urged Turkey to end its assault on Kurdish fighters in northern Syria.
In a statement (in French) it said it was "worried about the continued worsening of the situation".
On Saturday, Turkey began shelling the militia, which it says is linked to the banned Kurdistan Workers Party (PKK).
The fighters, the YPG militia based in Syria, have rejected Turkey's demand to leave areas it has seized, saying Islamists would return if it left.
Turkey's assault is a new thread in an already-complex conflict that has drawn in competing regional powers.
Turkish Prime Minister Ahmet Davutoglu insisted on Sunday that Turkey "will not permit the [Kurdish militia] to carry out aggressive acts".
"Our security forces gave the necessary response and will continue to do so," Mr Davutoglu said.
Syria has also condemned the Turkish action as a violation of its sovereignty and asked the UN Security Council to intervene.
France also called on the Syrian regime and its allies to stop their bombardments "across the whole of the country".
France said priority should be given to implementing an agreement reached in Munich this week on ceasing hostilities, and the fight against so-called Islamic State (IS) group.
Almost five years of civil war in Syria have led to the deaths of more than 250,000 people. More than 11 million people have been displaced, foreign media reports.