The French Football Federation (FFF) said on Sunday its ethics committee would investigate Nice player Youcef Atal for social media posts containing "calls for violence", linked to the Hamas-Israel conflict.
The Algerian international defender posted a video on Instagram account of a speaker making, according to people who saw it, anti-Semitic remarks calling for violence.
The post sparked outrage from French politicians.
It has since been deleted and AFP has been unable to independently verify its content.
On Sunday FFF president Philippe Diallo released statement denouncing "calls for violence relayed by the 27-year-old player".
"They are contrary to the ethics of our sport and the values that soccer relentlessly defends", he said.
"The FFF condemns them in the strongest possible terms. Hate speech cannot be tolerated," he declared, announcing that the FFF's national ethics council had been informed.
Atal apologised on Instagram on Sunday.
"I am aware that my publication shocked people, which was not my intention, and I apologise for that," he wrote, adding that he wanted to "clarify (his) point of view without any ambiguity: I strongly condemn all forms of violence, anywhere in the world, and I support all victims".
"I will never support a message of hatred. Peace is an ideal in which I firmly believe", he said.
Contacted by AFP, the Nice public prosecutor's office said it was not yet investigating.
Israel declared war on Hamas last Sunday, a day after waves of fighters broke through the heavily fortified border with Gaza and killed more than 1,400 people, most of them civilians.
Israel's response has left at least 2,450 people dead in the Gaza Strip, the majority ordinary Palestinians, the health ministry there said.