The official said it was unclear whether the 10 people trapped inside were being held hostage or were hiding from the gunmen.
The Villeneuve-la-Garenne Primark is one of 165 stores located in the Qwartz mall, where the hostage-taking happened, and one of five the brand has in France.
It is now understood all hostages have been released, but the gunmen have escaped.
A police source said two or three gunmen entered the store around 6:30 a.m. for an attempted robbery.
Police could not confirm whether the people had been taken hostage.
“Our main priority was ensuring their safety and we have done this”. Police forces across the region have been alerted.
Armed officers from a special police unit entered the store and emerged later with women reported to be store employees, according to images broadcast on BFM television.
“He and the other two were armed with pump-action rifles. We hope for a speedy and safe end to this incident”.
Police told the BBC the incident appeared to be an armed robbery, not a terrorist attack. The area around the shopping centre has been shut down.