French authorities this week arrested four people of Pakistani origin suspected of links to the meat cleaver attack in late September by a young Pakistani outside the former offices of the Charlie Hebdo weekly that wounded two people, a judicial source said on Friday.

The four were detained on Monday and one was already charged on Wednesday with taking part in a terrorist conspiracy, while the three others are now appearing before a judge with a view to being charged, added the source who asked not to be named.

They are suspected of being aware of the attacker's plot and inciting him to carry it out, said the source, confirming a report first published in the Le Parisien daily.

The attacker, named as Zaheer Hassan Mahmoud, 25, was arrested after the attack on terror charges and remains in custody.

The news of the arrests comes two days after a Paris court convicted 13 accomplices of the jihadist gunmen who massacred staff in January 2015 at Charlie Hebdo, which had published cartoons of Prophet Muhammad (PBUH).

To mark the start of that trial in early September, Charlie Hebdo had in typically provocative style reprinted the sketches.

Three weeks later, the Pakistani man wounded two people outside the magazine's former offices, hacking at them with a cleaver.

On October 16, a young Chechen refugee beheaded teacher Samuel Paty who had shown some of the caricatures to his pupils.

And on October 29, three people were killed when a young Tunisian recently arrived in Europe went on a stabbing spree in a church in the Mediterranean city of Nice.

President Emmanuel Macron's government has introduced legislation to tackle what he calls radical Islamist activity in France, a bill that has stirred anger in many Muslim countries.