Police officers secure the area where an attacker stabbed a female police administrative worker, in Rambouillet, near Paris, France, April 23,
Anti-terror prosecutors have taken over the inquiry, and the killing is being treated as a possible terrorist attack.
The attacker, who reportedly came to France from Tunisia several years ago, was shot dead by police.
President Emmanuel Macron led tributes to the 49-year-old victim, and said France would never give in to Islamist terrorism.
What do we know about the attack?
The stabbing took place in the secure entrance to the police station in the commuter town of Rambouillet at 14:20 (12:20 GMT).
Witnesses said the attacker had been seen walking around while on his mobile phone outside the police station and seized his chance to go in as the woman – an unarmed administrative officer – went through the security doors.
He reportedly lunged at the officer, stabbing her in the neck. Her colleagues then opened fire on him.
Anti-terrorism prosecutors said they took over the investigation because of the way the attack had unfolded, remarks made by the attacker and the fact that he targeted a police official.
Sources close to the inquiry told media outlets that the man had shouted Allahu Akbar (God is greatest) during the attack.
Officials said the attacker, 36, was not previously known to security agencies. Local outlet BFMTV reported that he had lived in the country illegally before obtaining a residency card, which was due to expire later this year.
Three people were arrested following the attack, according to reports. A judicial source told AFP news agency they were part of the suspects entourage.