A knife-wielding man has killed four officers at central police headquarters in Paris, according to French media.
The attacker, who has not been named but is said to be a member of staff, was later shot dead by police.
There has been no official statement so far. The area in the île de la Cité – in the centre of Paris – has been sealed off.
The attack comes a day after police went on strike across France over increasing violence towards officers.
Union official Yves Lefebvre said the attack happened around 1pm at the headquarters, located just across the street from Notre Dame Cathedral.
French Prime Minister Edouard Philippe and Interior Minister Christophe Castaner are both at the scene, reports say.
Paris mayor Anne Hidalgo confirmed on Twitter that “several people” had been killed in the attack, which took place near major tourist sites including the Notre-Dame cathedral.
The attack appeared to have begun in an office and spread elsewhere, Lefebvre said.
The knifeman worked at