A gunman has opened fire inside the central Paris office of left-wing daily Liberation and seriously injured one staffer.

The victim, a photographer's assistant aged 27, was hit in the thorax and in the stomach.

"He walked in, fired twice and left," said editorial manager Fabrice Rousselot told BFM TV.

The reasons for the attack are unclear.

The man entered the office shortly before 09.15am GMT, armed with a hunting rifle, and fired two shots before fleeing.

He was described as in his 40s, with a shaved head, wearing a long green coat and a bulletproof vest.

Editor of Liberation, Fabrice Rousselot, condemned the attack. He said it was "outrageous" that the press could be targeted.

On Friday, an armed man broke into the Paris offices of news channel BFMTV but did not fire.

According to authorities, the man was caught on CCTV and it appears to be the the same man that shot the photographer at Liberation's HQ.

Christian Fraser, BBC foreign correspondent in Paris, reported that all French media in the capital have been given heavy police protection:

A man also fired shots outside the Societe Generale's Granite Tower in the La Defense area of Paris but no one was injured.

French interior minister Manuel Valls said the gunman matched the description of the newspaper shooter.