Officials say knife attacker killed mother and sister and injured another before being shot dead by police in Paris

French officials say the two people killed in a knife attack on Thursday in Paris were the mother and sister of the attacker, who was subsequently shot by police.

The third victim, a passerby who was gravely injured in the attack, was also a woman, the official said.

Jean-Jacques Brot, the top government administrator in the Yvelines region, tweeted that the attacker Thursday in the town of Trappes was "neutralized" and had died.

The attack took place in a suburb west of Paris, Trappes on Thursday morning.

Two people were killed by an attacker in Trappes, West Paris. Credit: AP

Police officials said the man was flagged in a government database of suspected religious and political extremists.

The French interior minister says a man who killed his mother and sister in a knife attack west of Paris had "serious psychiatric problems."

Gerard Collomb said the attack in the town of Trappes on Thursday is not being treated as a terrorist case for the moment, despite a claim of responsibility by the Islamic State group.

French interior minister at the scene of the attack in West Paris. Credit: AP

Collumb noted the attacker suffered from serious mental health issues although he had also been flagged for glorifying terrorism.

The minister said police shot and killed the man after he came out of his mother's house wielding a knife and ignored their warnings.

French hooded police officers cordon off the area after a knife attack in Trappes. Credit: AP

The Islamic State group, has been known to make opportunistic claims in the past, even when there was no established link between an attacker and the extremist group.