French police are holding nine suspected Islamists as part of an anti-terrorism investigation.
Three were arrested today in southern France.
The other six detained yesterday in the Paris area have been described by the Interior Minister Manuel Valls as “particularly dangerous”.
They are being questioned by anti-terrorist investigators at Levallois, north of the capital. By law they can be held for up to four days.
Monday’s raids by anti-terrorist police took place in three towns around Paris.
Four of the six suspects are French, one is from Benin and the other from the Comoros Islands. They are all said to be aged in their twenties and thirties.
They are thought to have been involved in armed robberies including a hold-up at a bank near the capital in April.
Since the murders by one individual of seven people in Toulouse last year, several terrorist cells have been dismantled, according to the interior minister.
France raised its domestic terror alert level after its military intervention in Mali.