An Irish woman who was beaten on the head with a motorcycle chain lock in an apparently random attack in France has been released from hospital.

The 25-year-old was attacked by three men in the southern French town of Avignon.

The men set upon her as she returned to her lodgings in the centre of the town at around 7am on Saturday morning.

During the attack she was pushed and hit with the chain. She suffered serious injuries to the mouth, cheeks and nose, police said.

"She is in a state of shock," a police source told Le Dauphiné Libéré newspaper.

Local police were not immediately available for comment.

The men ran off after the attack, leaving the chain behind them on the Rue des Infirmières, where the young woman was staying in the southern city that draws hundreds of thousands of visitors every year.

The victim told police she did not know the identity of the attackers.

It is not yet clear whether the woman was living in the town or was there on holiday.

Police are trying to establish a motive for the attack.