Police in France have foiled a suspected terror attack using highly toxic poison and arrested two brothers of Egyptian origin, authorities have said.

Ricin or explosives are thought to have been prepared ahead of the planned attack, according to French Interior Minister Gerard Collomb.

The revelation came after a 29-year-old man was killed and five other people injured in a deadly knife attack in Paris last Saturday night.

Armed French police officers at the scene after the brutal attack in Paris just six days ago

'There were two young people of Egyptian origin who were preparing to commit an attack, with either explosives or ricin, this very powerful poison,' said Mr Collomb.

He did not indicate the nationality of the suspects or provide any other details about their arrest.

But a source close to the inquiry said the men were detained in the northern 18th Arrondissement of Paris on May 11.

Just a day later Khamzat Azimov, who also lived in the 18th Arrondissement, carried out his knife rampage in the capital.

Mr Collomb said the men had watched tutorials on how to make ricin-based poisons and communicated via the encrypted messaging app Telecom.

France has been the victim of a string of deadly attacks in recent years.

This is the first image to be made public showing Khamzat Asimov, the Islamic State terrorist who launched a knife attack in Paris on Saturday

President Emmanuel Macron's government is under criticism for not preventing attacks like the one on Saturday, when an Islamic extremist stabbed five people in central Paris, killing one of them.

The assailant in Saturday's attack, a 20-year-old Frenchman of Chechen origin, had been on a watch list for radicals, like several others who have attacked France in recent years.

The assailant was killed by police, and a close friend of his was arrested and given preliminary terrorism charges Thursday night.

In late March, Prime Minister Edouard Philippe indicated that 51 attacks had been thwarted by French security services since January 2015.

A total of 246 people have been killed in attacks since then.