One dead as French hostage standoff ends

French police have killed one man after his heavily armed group took the family of a bank manager hostage in a northern town but officials say there is no link to terrorism.

A group of heavily armed men wielding Kalashnikovs tried to seize the manager of a local bank branch in Roubaix to make him open the safe, local prosecutor Frederic Fevre said on Tuesday.

When police arrived, the manager escaped and the assailants instead holed up in his house in an upmarket neighbourhood of the town, taking his wife, their daughter and their 11-month-old baby hostage.

One of the suspects opened fire at police, prompting security forces to return fire, Fevre said.

After two hours, a specialist police unit launched an assault on the house, freeing the captives, killing one of the suspects and arresting a second in the back garden, Fevre said.

Other members of the group got away, although the precise number was unknown, Fevre said.

"It was a criminal operation" and not associated with terrorism, Fevre told reporters.

The incident came as France remained on a high state of alert following its worst militant attacks.

Roubaix lies about 100 kilometres from the Belgian capital of Brussels, which is on an unprecedented security lockdown.

On November 13, gunmen and suicide bombers killed 130 people in simultaneous attacks on a concert hall and restaurants in central Paris and on the national stadium to the north of the French capital.