French President Francois Hollande said a terror cell had been shut down and an attack "foiled," after Ines Madani, 19, and two other women were arrested.
Police shot and wounded Madani as they swooped on her and her accomplices aged 23 and 39 in a suburb south of Paris yesterday.
Investigators believe Madani is the main suspect in a probe into the Peugeot 607 found a few hundred metres from Notre Dame cathedral on Sunday. She is the daughter of the car's owner.
The women were "radicalised and fanaticised", he said.
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Madani had sworn allegiance to the Islamic State group in a letter found in her possession, according to a source in the investigation.
A police officer suffered a knife wound to the stomach during the arrests late yesterday in Boussy-Saint-Antoine, south of Paris.
Hollande, speaking on a visit to Athens, said: "An attack has been foiled."
"A group has been destroyed," he said, but he warned: "There are others."
A police source said security services had issued a warning yesterday about a possible attack on train stations in Paris and the area where the women lived.
The car was discovered with its hazard lights flashing and its licence plates had been removed.
Three bottles of diesel fuel were also discovered in the vehicle, but police did not find any detonators.
Police said the boyfriend of one of the three women was arrested yesterday.
The man's brother is himself in custody over suspected links to Larossi Abballa, a jihadist who killed a police officer and his girlfriend in a Paris suburb in June, a source said.
The first couple arrested, a 34-year-old man and a 29-year-old woman, have been held since Tuesday and are known to the security services for links to radical Islam.
Police then arrested the man's brother and his girlfriend, both aged 26.
France is on high alert after Islamic State called on its followers to attack the country in revenge for air strikes on the group's bases in Syria and Iraq.
IS has claimed responsibility for a string of jihadist attacks, including last November's coordinated bloodshed in which gunmen and suicide bombers killed 130 people.