French police on Friday detained Algerian international Youcef Atal, who plays for Ligue 1 football side Nice, in a probe into suspected "justification of terrorism" after he published a social media post on the Israel-Hamas war, prosecutors said.
Last month the 27-year-old defender was banned for seven matches over the post, which he quickly deleted and for which he subsequently issued an apology.
The public prosecutor in Nice opened a probe following a request from the local prefect and mayor of Nice.
The arrest means Atal can now be questioned by police in detention and could be charged, or released with no further immediate action taken, once the detention period expires.
Atal had already been suspended by his club "until further notice".
Despite the player's apology, OGC Nice said that it decided to "take immediate" action, "prior" to any sanctions that might be taken by sporting or judicial bodies, "given the nature of the publication shared and its seriousness".
In mid-October, the Nice public prosecutor announced the opening of an investigation into "justification of terrorism."
Atal has been criticised for sharing a video from a Palestinian preacher on Instagram, purportedly calling for violence against Jewish people.
AFP was unable to independently verify its content.
France, which has large Jewish and Muslim populations, ramped up security after Hamas launched massive attacks on Israel on October 7.
Israeli officials say the attacks killed 1,200 people, mostly civilians, and about 240 people were taken hostage.
Israel has vowed to destroy Hamas and its retaliatory air and ground offensive in the Gaza Strip has killed nearly 15,000 people, thousands of them children, according to the Hamas government of the Palestinian territory.
AFP