Their identities were not disclosed, but police had said they were looking for four men seen raping the 19-year-old woman in videos posted on Snapchat and Twitter last month.
The footage taken in a club's parking lot in Balma, a suburb of Toulouse, sparked a wave of outrage, with many people claiming to know the identities of the attackers.
Local police were alerted to the attack after the videos were flagged to France's national digital surveillance cell, and the victim herself came forward after learning the videos were circulating on social media.
The videos were deleted by the interior ministry's Pharos programme for tracking and removing graphic and violent internet content, and police urged people not to share the images.
Videos of rapes have become an increasingly common problem online due to the spread of mobile phones and social media usage, with cases in the United States, Brazil and India causing disgust in recent years.
People who shared the videos could face up to five years in prison if they are apprehended, while the bystanders who filmed the rape could also face lengthy terms for complicity in the attack.