The Associated Press reports that some French media outlets are beginning to react skeptically to the 23-year old woman's account of her attack. In particular, France-Info radio and the television station LCI are increasingly skeptical; however I find the bases for doubt to be unconvincing. The following problems with the woman's story have been posited:
(1) "Surveillance cameras at the station where the culprits reportedly left the train showed no young men running from the scene." If the men attacked a woman and her child in a train full of individuals and no one came to her aid, why would the offenders run away from the train station? What would they be fleeing? And wouldn't a group of six teenagers racing through the station attract the attention of the police?
(2) "no witnesses have come forward despite repeated calls from officials and promises of anonymity." First, French law punishes non-feasance (i.e. you have a legal obligation to assist a person in danger), although the French police have claimed that they will not prosecute anyone who steps forward. Second, even if guaranteed immunity, who would want to come forward after having failed to help the woman?
(3) "the young woman had filed several [allegedly 6] complaints about violence and aggressive treatment in the past." Six sounds like a lot, but it's not inconceivable that a young woman might be harassed multiple times in a big city.
The woman's story should be subject to scrutiny; however I can find no reason, as of yet, to discount her story based on the reasons emphasized by France-Info and LCI.