Elite police commando units were carrying out several counter-terrorism in the Paris suburb of Argenteuil on Thursday afternoon, according to reports in the French press.
The raids, which began around 2.30pm were being carried out at two separate addresses in the suburb but it is unclear at this stage what had prompted the police to act.
French news channel Itéle quoted police sources saying the raids were being carried out by internal intelligence services and specialist Swat teams from the elite police unit Raid.
A police told Le Figaro newspaper that the raids were ordered after an intelligence tip off from an anonymous member of the public and had no connection with the Nice attack. The information given to police suggested a violent attack may have been being planned, the source told the newspaper.
Security cordons had been set up around the site where the raids were taking place. Later reports from the French press stated 20 individuals had been arrested but not guns or explosives had been found.
Initial reports that suggested a mosque and a Muslim bookshop were targeted in the raids were later believed to be false.
French authorities have not officially confirmed the motive for the raids that took place in the same suburb of Argenteuil that saw a major counter-terror operation in March that led to the arrest of Reda Kriket,
The French government believes Kriket was plotting to carry out an attack during the Euro 2016 football tournament.
He was arrested in possession of Kalashnikovs and explosives and had links to the terror network behind the Paris and Brussels attacks.
"The arrest is the result intricate work carried out over the last few weeks by intelligence services," Interior Minister Bernard Cazeneuve said at the time.
The minister confirmed the man arrested was of French nationality and was "involved in the plot at a high level" and that he was "involved in a terrorist network that was ready to attack France."
Thursday's operation comes as France remains on high alert for terrorism attacks, following last Thursday's truck rampage in Nice that left 84 dead.