French prosecutors have denied a report that police had arrested a man believed to have opened fire yesterday at the offices of a left-wing newspaper and a major bank in Paris.

Le Parisien newspaper had reported that an arrest had been made.

French police have been seeking help from the public in capturing the fugitive gunman and circulated pictures of his face yesterday.

The gunman burst into the headquarters of daily newspaper Liberation yesterday, shooting and critically wounding a 23-year-old photographer's assistant before fleeing.

Soon afterwards he fired at least three shots into the lobby of the headquarters of Societe Generale bank in the La Defense business district, 10km west of the city centre, according to Paris prosecutor Francois Molins.

A window was shattered but there were no casualties.

The gunman subsequently vanished into crowds near the central Champs-Elysees boulevard after forcing a motorist at gunpoint to take him there.

The gunman has not given any indication of his motive.