Three men have also been taken into custody by special forces and a man and woman have been arrested close to the St Denis flat.
Among those arrested by police is the possible owner of the apartment where the suspects are believed to have been holed up in Saint-Denis, AFP reports.
The man, who was not named, said he provided accommodation for two people in the apartment at 8 Rue du Corbillon after a friend asked him to do so. She told him they came from Belgium and needed a place to stay.
The target of police action in the Paris suburb of St Denis is the Islamic State militant, Abdelhamid Abaaoud, who was initially thought to have orchestrated the Paris attacks from Syria, police and justice sources said.
French media also reported that at least two people had been killed. There are also reports of a woman who detonated a suicide belt.
People living in or near St Denis have been subjected to rigorous security checks, as the operation in the suburb continues. The area itself has been sealed by the military.
Shops and schools have also been closed and transport was suspended.
Police, however, said that they believe the suspected mastermind of last week’s attacks, Abaaoud, is holed up in an apartment in Saint Denis, along with up to five other heavily armed people.
The official, nonetheless, said that scores of police, who stormed the building early on Wednesday were met with unexpectedly violent resistance.
Reinforcements were summoned and several people were injured.
French investigators believe that a Moroccan-origin Belgian jihadist masterminded the Paris attacks which killed at least 129 people.
Abaaoud is thought to be in Syria now with the Islamic State (ISIS) group.
The 27-year-old, grew up in Molenbeek, a district of Brussels known for its many Arab immigrants, blighted by high unemployment and overcrowded housing.
He is an associate of Salah Abdeslam, who is on the run and whose brother Brahim, blew himself up in Paris.