“If it turns out that this operation takes a turn other than fighting a potential terrorist threat to the Turkish border and becomes an invasion, that is a real problem for us,” Macon said in an interview with Le Figaro newspaper published on Wednesday.
Turkey launched its Operation Olive Branch on 20 January, enrolling Free Syrian Army fighters in its assault on areas held by the Syrian Kurdish People's Protection Units (YPG), which it accuses of being "terrorists" and members of the same group as the Kurdistan Workers" Party (PKK) that has been fighting Turkish state forces for three decades.
Last week it announced it was stepping up the operation with the intention of capturing the town of Manbij, where US troops are working with the YPG.
The United States and France have armed and trained YPG-led militia in the fight against Islamic State in Syria.
Macron said he would discuss the question with Turkish President Recep Tayyip Erdogan over the next few days and that the nature of the operation meant there should be discussions between Europeans and more widely among allies.
Armenian genocide commemoration
Macron was speaking after a dinner organised by Armenians in France, where he was the guest of honour.
He promised the 500 Franco-Armenians present that France will soon have a day of official commemoration of the Turkish massacres of some 1.5 million Armenians during World War I, as he promised during the presidential election campaign.
Turkey protested vigorously in 2012 when France officially recognised the killings as genocide.
Community leaders Ara Toranian and Mourad Papazian called on the president to condemn Turkey for its present-day policy towards minorities, including Armenians.
Macron defended his strategy of dialogue with Erdogan, who visited the Elysée presidential palace this month.
"Many people doubt the wisdom of this dialogue with Turkey," he conceded. "But I consider that would condemn France's message to being an injunction in a vacuum."