French police have been hunting a lone gunman who opened fire on the offices of left-wing newspaper Liberation and the headquarters of a major banking services company in Paris.

The attacker, who police said was filmed by video-surveillance cameras, fired shots on Monday at the newspaper office seriously wounding one, before hijacking a car to take him to the Champs-Elysees avenue, police and staff at the newspaper said.

About 90 minutes later, he opened fire outside the headquarters of the Societe Generale bank in the La Defense business district, 10km from the centre, police and a spokeswoman for the bank said.

Earlier, Fabrice Rousselot, the managing editor of Liberation, said witnesses described the assailant as a short-haired man in his 40s. Police said he was "of European type".

Police deployed outside the offices of other media businesses in the French capital. A police helicopter hovered over the Champs-Elysees area to help in the manhunt.

French President Francois Hollande, speaking from Jerusalem, said he had asked his Interior Minister to use all possible means to find the gunman, "who tried to kill and could still do so". 

"Freedom of the press is being targeted," Hollande, who is on the tour of Israel, told the French media.

The mid-morning incidents came days after an armed intruder entered the offices of the BFM TV channel, threatening journalists before disappearing. Police said video surveillance footage indicated it could be the same man.

Police said the description of the robber fitted that of the gunman, who was armed with a hunting rifle or similar weapon. Cartridges found after both attacks corresponded. 

"Given the similarities between these four cases... we are favouring the hypothesis that there is one author," said Paris prosecutor Francois Molins told journalists.

Source: Agencies