French police have ruled out terrorism as a motive after a van rammed into two Marseille bus stops, killing a woman at one of them.
A police official said "the terrorist motive is completely rejected" for the incident on Monday morning.
Police had already said that the driver of the white van that hit the bus stops in two neighbourhoods is being treated for psychological problems.
The 35-year-old suspect was arrested in the Old Port neighbourhood of France's second largest city.
The collisions at the bus stops about five kilometres (three miles) apart came days after back-to-back van attacks in Barcelona and the Spanish resort town of Cambrils killed 15 people.
The Islamic State group claimed responsibility for the double attacks.
It was the second time in a week that a driver in France with mental health problems allegedly killed a person with a vehicle and was thought by authorities to have acted deliberately, but without terrorist intent.
The Marseille driver, who has not been identified by name, is being held for questioning.
BFM-TV said a witness noted the van's licence plate number and was able to give it to police, allowing them to make the arrest.
Nearly an hour passed between when the first bus stop was slammed into and the second, the police official said.
She could not confirm reports in the regional newspaper La Provence that the white van had been stolen.
A man was injured at the first bus stop in a working class northern district filled with housing projects, David-Olivier Reverdy of the Alliance police union said.
The van later rammed into another bus stop in a second neighbourhood, killing a woman.
The driver steered onto the curb to crash into the glass-sided bus shelter then sped away, one witness said.
"We heard a loud noise, like a car accident, and we came to figure out what happened," Nicolas Negre, 32, an employee at a nearby fast food restaurant, said.
"We saw... a person lying inert, with blood on her, and the van leaving very quickly, moving fast, burning rubber."
He said the gruesome scene made clear that "he had to climb the pavement... he hit and then left very quickly".
La Provence reported that the suspect came to Marseille specifically for psychiatric treatment in a specialised institution.
The paper did not name its sources and the police official could not confirm the report.
On August 14, a driver rammed his car into a crowded pizzeria east of Paris, killing an adolescent girl and injuring a dozen other people.
A prosecutor has described the driver, a 32-year-old security guard, as under the influence of drugs and showing signs of paranoia, but not motivated by extremist views.
He is facing murder charges after a psychiatric exam determined his judgment was not impaired and he could be held legally responsible for his actions.