At least five people have been taken hostage at a kosher supermarket in Paris after a shootout, the Reuters news agency said, reprts Sky News.
The suspect was armed with two guns, the agency quoted a police source as saying.
Reports said that one person was wounded in the attack in the eastern part of the French capital, as SWAT teams surrounded the area.
Kosher restaurants were closing across Paris.
The gunman was suspected of being the same man who killed a policewoman in Montrouge, southern Paris, on Thursday.
He is thought to have links to the assailants who stormed satirical magazine Charlie Hebdo a day earlier, killing 12 people.