Those detained were close to the suspected assailant, police sources say. The officers were saved thanks to their bulletproof vests.
Three people have been arrested after a group of police officers were attacked in the southern French city of Cannes.
The three who were arrested were close to the suspected assailant, police sources told AFP, including someone who worked for the man and another who housed him.
The attack occurred around 06:30 on Monday morning in front of Cannes' main police station when a man opened the door of a parked police vehicle and stabbed an officer in the chest before stabbing another officer in the car. The officers were protected by their bulletproof vests.
A third police officer then shot and seriously injured the attacker with their weapon, according to the Grasse public prosecutor. A fourth officer fired through the window of the vehicle.
The attacker is a 37-year-old Algerian national who held an Italian residency permit.
France's Interior Minister Gérald Darmanin, who visited the scene, said the suspect was not previously known to the police and intelligence services.
"I think we can breathe a sigh of relief", Darmanin told reporters in front of the Cannes police station.
On Tuesday, police announced that they had also arrested three people on suspicion of assisting the attacker.
"We are still trying to understand the motivations of the perpetrator," the police source said.
Eric Ciotti, a French representative from the Alpes-Maritimes region who is also running for president, called it a "terrorist attack" but others have been more cautious.
"All my best wishes for a speedy recovery to the policewoman and police officers injured at the Cannes police station during a terrorist attack," Ciotti wrote, as he travelled to the scene.
The anti-terrorism prosecutor has not been put in charge of the investigation.