A auto deliberately plowed into a crowd of students in France on Friday, injuring three people, including two who were hurt seriously, police said.
Police say the man is known for previous minor offences, especially drugs-related.
"What matters in this case is the psychiatric profile of the person", he added.
Toulouse prosecutor Pierre-Yves Couilleau, said his office had opened an attempted murder investigation "because the driver was planning to mow people down". There are fears of a terrorist attack.
The investigation is to be handled by regular judicial police rather than Paris's anti-terror unit, he said. A 23-year-old is more seriously injured, a young man and another girl, aged 22 and 23, have lighter injuries.
The woman's life is not in danger, police said. They were all thought to be of Chinese origin.
The incident occurred outside a college in the suburb of Blagnac.
France has been victim of a series of vehicle attacks by extremists inspired by the Islamic State group, but there was no immediate confirmation of the driver's identity or motive.
Last summer, a Tunisian man used a large truck to kill 86 people in the southern French city of Nice.