Officers detained the couple during a routine traffic stop in Port-de-Bouc, and are believed to have also recovered ammunition from the vehicle.
The 25-year-old man had previously been referred to police for abusing his partner, who was arrested alongside him.
He is believed to have been issued with a restraining order forbidding him from contacting the woman before the incident.
While the man reportedly has a criminal record for petty crimes, he is not believed to be linked to any terror groups.
Earlier this week ISIS claimed Sunday’s attack in Marseille after officials confirmed the incident was a “likely terrorist act”.
After stabbing the women, aged 17 and 20, the assailant was shot dead at Gare de Marseille-Saint-Charles station by a soldier in the southern French port city on Sunday.
A witness told Reuters she saw a man take out a knife from his sleeve and then stab a young girl and then a second woman, shouting what could have been “Allahu Akbar”.
The assailant was neutralised by a soldier from a military Sentinelle patrol, a force which was deployed across the country after a state of emergency was declared following ISIS attacks almost two years ago.
Marseille mayor Jean-Claude Gaudin said: ”We have until now managed to avoid such dramatic incidents in Marseille.
“I think it was a terrorist attack and the individual who was killed seems to have had several identities.”
Interior Minister Gerard Collomb said the man had initially killed one woman and looked to be running away before returning to attack a second woman.
Mr Collomb added: “This could be an act of terrorism, but we cannot confirm it fully at this stage.”
In a statement, the Foreign Office said: “Following an incident at Marseille St Charles train station we are advising British nationals in the vicinity to take care and follow the advice of the local security authorities.”