Two brothers suspected of being the gunmen behind an attack on the satirical newspaper Charlie Hebdo, which left 12 people dead, have been killed after being cornered by French police.

Cherif and Said Kouachi were at the centre of a stand-off at a printing business in an industrial area in Dammartin-en-Goele, around 40 kilometres from the area police were searching on Thursday.

Police launched an operation to "neutralise" the suspected gunmen and free a hostage after a car chase that saw shots fired.

In a separate incident linked to the killing of a policewoman at a metro station on Thursday, a man with links to the Kouachi brothers took hostages in a kosher grocery store in eastern Paris.

Amedy Coulibaly killed at least two hostages before police stormed the building and freed several others including a child. A total of four hostages were killed.

Read the story or look back over the developments in our blog.