Police said one suspect had been detained after the attack, which occurred as the trial was underway for the alleged accomplices of the 2015 Charlie Hebdo attack.
A Paris police official said that while authorities initially thought two attackers were involved, they now believe it was only one person, who was detained near the Place de la Bastille in eastern Paris.
France 24 journalist Christophe Dansette at the scene said the suspect taken into custody was “covered in blood”.
Police initially announced that four people were wounded in the attack, but the official told The Associated Press that there are in fact only two confirmed wounded. Police could not explain the discrepancies.
“A serious event has taken place in Paris,” said Prime Minister Jean Castex, who was addressing reporters when the attack occurred and cut short a visit to northern Paris to head instead to the crisis centre of the interior ministry.
“Four people have been wounded and it seems that two are in a serious condition,” he said at that time.
The prime minister added the attack had taken place “in front of” the weekly’s former offices in the 11th district of central Paris. The magazine’s current address is kept secret for security reasons.
The stabbing came as a trial was underway in the capital for alleged accomplices of the instigators of the January 2015 attack on Charlie Hebdo.
Twelve people, including some of France’s most celebrated cartoonists, were killed in the attack by brothers Said and Cherif Kouachi and claimed by a branch of Al Qaeda.
A female police officer was killed a day later, followed the next day by the killing of four men in a hostage-taking at a Jewish supermarket by gunman Amedy Coulibaly.
The 14 defendants stand accused of having aided and abetted the perpetrators of the 2015 attacks, who were themselves killed in the wake of the massacres.
The magazine, defiant as ever, had marked the start of the trial by republishing hugely controversial cartoons of the Prophet Mohammed that had angered Muslims around the world.
Al-Qaeda then threatened Charlie Hebdo with a repeat of the 2015 massacre of its staff.
The trial in Paris had resumed Friday after a suspect’s coronavirus test came back negative.
The hearing for the fourteen suspects, which opened on September 2, was postponed Thursday after Nezar Mickael Pastor Alwatik fell ill in the stand.
His lawyer Marie Dose said her client had suffered from “a lot of fever, coughing, vomiting and headaches”.
He was back in the box on Friday, after the presiding judge informed defence and prosecution lawyers by SMS late Thursday that the test results allowed for the trial to go ahead.