Police have arrested a man in the Paris region as part of the investigation into the 13 November attacks in the city, sources say.
Some 2,700 raids have been conducted since the attacks, with 360 people placed under house arrest across France, the AFP news agency reports.
Police have also arrested two people in northern France suspected of supplying weapons to one of the gunmen in earlier attacks on Paris, reports say.
They were taken in for questioning.
The 29-year-old man arrested on Tuesday was planning to travel to Syria, according to one French media report.
The Paris prosecutor’s office says the two people arrested in northern France were held on suspicion of helping to provide guns to Amedy Coulibaly, who attacked a kosher supermarket in January.
The prosecutor’s office confirmed that the man arrested was Claude Hermant, who is known to have links to far-right groups, while the other is his partner.
Coulibaly killed four people inside the supermarket, and separately a policewoman, before dying in a shootout with police.
Meanwhile, a prominent Islamist preacher, Sven Lau, has been arrested in Moenchengladbach, western Germany, on suspicion of supporting a group linked to Islamic State militants, and recruiting fighters for it.
Lau – a convert to Islam – is known for a series of controversial initiatives, like setting up so-called sharia police controls, to enforce Islamic rules in the western city of Wuppertal.
The state interior minister for North Rhine-Westphalia, Ralf Jaeger, said the state authorities were trying to monitor hundreds of Islamists they believed were willing to use violence. He said Sven Lau played an important role in trying to radicalize people:
“He is one of the leading figures of the Salafist scene. He is someone who is trying to infect other young people with this extremism. He openly campaigns for terrorist organisations. That’s clearly dangerous because more and more people slip into this scene.”
Two independent eyewitnesses have told the BBC that they saw the ringleader of November’s Paris attacks, Abdelhamid Abaaoud, on the Greek island of Leros in October, placing him there at the same time as two Stade de France suicide bombers travelled through.
These sightings support French newspaper reports on Monday, quoting French and Moroccan security officials, who said this was highly likely.
It is known that the two Stade de France bombers arrived on Leros aboard smugglers’ boats on 3 October, then left for Athens with four other men, who have not been seen since.
A travel agent in Leros, who unwittingly sold the two bombers ferry tickets to Athens, says he is reasonably sure he also served Abaaoud, who stood out from hundreds of other migrants because he spoke French.
A trustee at the main island hospital also claims Abaaoud came to the hospital to be treated for a minor leg wound. He claims Abaaoud appeared nervous and suspicious, and offered a $110 bribe to jump the treatment queue.
Belgian and French officials say Abaaoud, a Belgian Islamist of Moroccan descent, organized November’s attacks which killed 130 people.
He was known to have been living in Athens in January this year, but fled to Syria after a failed attempt by Belgian police to catch him.