French police are seeking a young woman after a car carrying seven gas cylinders was discovered near Notre-Dame cathedral in Paris, police and judicial officials have said.

A couple, aged 34 and 29, were also arrested on a motorway in southern France in connection with the incident and remain in custody, one official told Reuters on Wednesday.

The car owner – who officials said was on an intelligence services watchlist of people suspected of religious radicalisation – was arrested but later released because he had gone to police on Sunday to report that his daughter had disappeared with his car.

His daughter, now sought by police, is 19 years old and was known to police for having the intention of leaving for Syria, officials said.

The car owner told investigators that his daughter was radicalised, according to a police source quoted by Agence France-Presse.

The Peugeot 607, which had no registration plates, contained seven gas cylinders, one of them empty, on the front passenger seat, police said.

It was found on Saturday with its hazard lights flashing as if to attract attention, they said.

Interior minister Bernard Cazeneuve said he was waiting for a report from investigators on what the possible motives were for the incident.

There was no detonating device present in the car, found on a Seine riverside stretch called the Quai de Montebello, metres from the Notre-Dame cathedral, one of Paris’s many popular tourist attractions. Documents with writing in Arabic were also found in the car.

More than 200 people have been killed in terror attacks in France over the past 18 months.

France remains on maximum alert after Islamic State called on its followers to attack targets in the country, which is bombing Isis bases in Iraq and Syria.

Florence Berthout, the mayor of Paris’s fifth arrondissement (district), said the incident highlighted the need to beef up security and put more police on patrol in one of the world’s most visited cities.

She said the vehicle was left in a zone where parking is strictly prohibited and that it had remained there for around two hours before it came to the attention of police. “Police and army staffing must be stepped up,” she told the news TV channel BFM.

Thousands of extra police and soldiers have been deployed to patrol sensitive sites across France since 130 people were killed by Islamist gunmen and suicide bombers in multiple attacks in Paris on 13 November last year.