A former French leftwing parliamentary candidate has been arrested over his tweets about a policeman killed during a jihadist siege in southern France last week, reports BBC News.
Stéphane Poussier appeared to celebrate the death of Lt-Col Arnaud Beltrame.
He added that the death in the town of Trèbes meant one less voter for President Emmanuel Macron.
French media say he could be charged with apology of terrorism.
Mr Poussier's Twitter account has since been deleted. It is unclear if this action was taken by him or the platform, after the tweets caused an outcry and were reported by other social media users.
The ex-candidate said the death made him think of a friend, activist Rémi Fraisse, who died after police threw a concussion grenade during protests in 2014.
Col Beltrame, 44, died after being shot when a jihadist stormed a supermarket in Trèbes on Friday.
Friday's attack - which killed four people - was the worst jihadist attack under Emmanuel Macron's presidency.