The 28-year-old, with a history of psychiatric problems, appeared before a judge who placed him in custody, prosecutor Pierre-Yves Couilleau said, adding that the man maintained an initial claim that voices in his head sparked his action.
The prosecutor had indicated the incident was not terror related.
The suspect, a single man who lives with his mother in Blagnac, a suburb of the city of Toulouse, had previously suffered severe psychiatric problems and was released from a court-ordered hospital stay in December 2016.
The incident hospitalized two of the students, in their early 20s, from the city's International Business School but the prosecutor said their condition was not serious.
Their fellow victim left hospital as did a French student aged 23 who suffered shock after witnessing the incident.
The suspect has a criminal record including drugs and armed robbery which brought him two suspended sentences and an order to receive treatment, which he was complying with, the prosecutor said.
The attack came days after China asked France to "ensure the security" of its nationals, who have been regular victims of thieves.
On November 2, a group of around 40 Chinese tourists were attacked with tear gas and robbed outside a three-star hotel near Orly Airport in Paris.