Doubts are growing about a reported anti-Semitic attack on a woman and her baby that stunned France.
The reported assault follows a rise in anti-Semitic attacks
Police have found no evidence or witnesses, four days after the alleged assault took place on a train in the suburbs of Paris.
The 23-year-old woman said six men cut her clothes and drew swastikas on her body, accusing her of being Jewish.
It sparked widespread condemnation amid concern that racist and anti-Semitic attacks are on the rise in France.
Police are advising caution as their investigations continue, noting that there are some contradictions in the woman's account.
The woman said she was attacked on a suburban train on Friday. The gang, who mistook her for a Jew, cut her hair, slashed her clothes and daubed her body with swastikas, she said.
The men, described as of North African appearance, are also said to have tipped her 13-month-old baby from her pram. According to the woman, about 20 people could have seen the attack but so far no-one has come forward.
Investigators have also been studying footage from surveillance cameras at the train station where the six alleged attackers were supposed to have got out but have found nothing.
French media report that the young woman has filed several complaints in the past about being the victim of violence.
The reported brutality of the attack on the woman, its anti-Semitic character and the fact that no-one came to her help provoked outrage.
It also added to growing concern over racist and anti-Semitic attacks.
President Jacques Chirac, who condemned the assault as "shameful", said he would deny clemency to any prisoner serving time for a racist crime.
Prime Minister Jean-Pierre Raffarin said: "Anti-Semitism is a disgrace. We want to fight this kind of intolerable racism."