The two victims of the Marseille knife attack were identified by their first names as cousins and best friends Mauranne and Laura, both 20.
Mauranne was from Eguilles, a town near Aix-en-Provence, and was studying medicine at Marseille university, where she lived on campus.
Yvon Berland, the president of the university, said she was a "brilliant student", who would have enjoyed a "superb professional future".
Laura lived in Rillieux-la-Pape, on the outskirts of Lyon, and had travelled to Marseille to celebrate her upcoming 21st birthday with her cousin and other friends.
Laura was in the second year of a course to qualify as a nurse in Lyon, and was also a scout leader, having joined the scout movement as a volunteer three years ago.
The two women were sitting on a bench outside Marseille's main train station waiting for Laura's train home when they were stabbed to death by the suspected Islamic State knifeman on Sunday.
The man shouted "Allahu Akbar" as he murdered the women outside St-Charles station in the southern city of Marseille on Sunday afternoon.
Shocked passers-by looked on in horror as he used a butcher's knife to carry out the attack, before he was himself gunned down by a military patrol on anti-terrorism duties.
French prosecutors have said the man presented a Tunisian passport when arrested last week.
Despite ISIS claiming responsibility for the attack, investigators have not found any link so far between the assailant and the terror group.
The man, who was aged between 30 and 35, has not been formally identified.
On Friday the attacker - who was a North African of either Algerian or Tunisian origin - was arrested in Lyon for shoplifting.
He had no papers on him and was in "an irregular situation in Europe", so giving the authorities a chance to place him under judicial control.
"Instead they let him go, and the next they heard about him was in connection with a double murder," said an investigating source in Marseille.
"Forensic evidence has linked him with the incidents in Marseille and in Lyon, but his actual name and other details remain in dispute.
"He was known to police for his links to drug-related crimes, but had used up to eight identities over the past few months."
The source said the killer, who was not on a terrorist watch list, had no links with radicalisation, despite Islamic State claiming responsibility for his station attack.
French President Emmanuel Macron has said he is "deeply outraged by this barbaric act" and "sharing the pain" of all those involved.
He said he "saluted" the soldiers from Operation Sentinel, an anti-terrorism initiative, who "reacted with extreme calmness and efficiency" as they killed the man.
Jean-Claude Gaudin, the Mayor of Marseille, has described the atrocity as a "terrorist attack", while Interior Minister Gerard Collomb said it "could be" related to terror.
It is thought to be the latest in a long series of Islamic State atrocities across France and the rest of Europe.
In April, 39-year-old police officers Xavier Jugele was shot dead while on duty on the Champs Elysee just days before the French presidential election.
Isis claimed the killing by Karim Cheurfi, also 39, who was shot dead by police in a gun battle. Two other officers were injured in the attack.
In June a student student shouted "This is for Syria" as he tried to attack a policeman with a hammer outside Notre Dame Cathedral in Paris. He was shot and ended up in custody in hospital.
And in March a convicted criminal with links to radical Islam shouted, "I am here to die for Allah, there will be deaths" seconds before he was shot dead during an attack at Paris Orly airport.
Ziyed Ben Belgacem, a 39-year-old career criminal, was killed after wrestling a soldier's gun from her and fleeing into a McDonald's restaurant.
It followed the shooting in February of a man outside the Louvre museum in the heart of Paris after he attempted to storm the historic art gallery.