"The punishment must be harsh, the enquiry has just started, arrests have been made," Manuel Valls told RTL radio.
A rare rally by police to protest against "anti-cop hatred" descended into violence on Wednesday, with a small group hammering a police vehicle with iron bars before hurling an explosive device inside. This all happened while the officers were still inside.
See footage of the attack below, which starts at around the 3min30 mark.
The police rally took place in Place de la Republique, the focal point for the youth-driven "Up All Night" movement that emerged out of the protests against the Socialist government's controversial labour reforms.
The burning police car on Quai de Valmy in northeastern Paris. Photo: AFP
Paris police chief Michel Cadot said the officers "were in the car when the explosive device was thrown inside", an account confirmed by a surveillance video seen by AFP.
The two officers -- one man and one woman -- managed to flee the vehicle.
A sign reading "roasted chicken, pay as you like" was placed in front of the burnt out police car. Photo: AFP
The incident came as some 300 people defied a ban to march through the streets chanting "Cops, pigs, killers!" as police forced the demonstrators back with volleys of tear gas.
Four suspects were arrested on Wednesday and a fifth was picked up on Thursday, sources close to the investigation said.
Several rallies in recent weeks -- often against controversial labour reforms proposed by the deeply unpopular government of President Francois Hollande -- have erupted in violence.
Small groups of troublemakers appear to have infiltrated the demonstrators and are bent on attacking security forces.
Valls called on the organisers of some demonstrations to prevent troublemakers from mingling with the crowd.
Over the past two months, some 350 members of the security forces have been injured during protests against the proposed labour reforms, which were forced through the lower house of parliament last week without a vote.
A plainclothes officer was seriously injured after being hit in the head by a projectile at a Paris protest last month.
Philippe Lavenu, from leading police union Alliance, said that officers were fed up with the "anti-cop hatred", which shows a marked difference from when crowds would cheer the police after the January terror attacks last year.
"We have gone from being embraced by the crowds after the Charlie Hebdo killings to being attacked repeatedly in the streets," he told The Local earlier this month.