The state of emergency expands police powers to carry out arrests and searches, and allows authorities to forbid the movement of people and vehicles at specific times and places.
Prime minister Manuel Valls had pressed for the state of emergency extension, warning that Islamic extremists might use chemical or biological weapons.
“Terrorism hit France not because of what it is doing in Iraq and Syria ... but for what it is,” Mr Valls told politicians.
“We know that there could also be a risk of chemical or biological weapons.”
Mr Valls did not say there was a specific threat against France involving such weapons, however.
Elsewhere in Europe, jittery leaders and law enforcement moved to protect their citizens as Rob Wainwright, director of the European Union’s police co-ordination agency Europol, warned of “a very serious escalation” of the terror threat in Europe.
In Italy, foreign minister Paolo Gentiloni said law enforcement was searching for five people flagged by the FBI in response to a US warning about potential targets following the Paris attacks.
The US state department issued a warning that St Peter’s Basilica in Rome, Milan’s cathedral and La Scala opera house, as well as churches, synagogues, restaurants, theatres and hotels, had been identified as “potential targets”.
Danish and Norwegian police were asked to be on the lookout for a man who Swedish authorities said is wanted in connection with an investigation into “preparing for a terrorist offence”.
Sweden’s security service, known as SAPO, said the request was not linked to the Paris attacks.
In Belgium, where many of the Paris attackers lived, prime minister Charles Michel announced a package of additional anti-terror measures, and said €400 million would be earmarked to expand the fight.
French foreign minister Laurent Fabius urged the international community to do more to eradicate the Islamic State group, which has claimed responsibility for the November 13 attacks on a rock concert, Parisian cafes and the national stadium.
Mr Fabius, speaking on France-Inter radio, said the group “is a monster.
"But if all the countries in the world aren’t capable of fighting against 30,000 people (IS members), it’s incomprehensible”.