French prime minister Manuel Valls has sought to ease concerns over a spate of seemingly unrelated but bloody attacks in France, saying up to 300 soldiers would be deployed around the country to ensure security.

Three separate acts of violence in three days has left one dead and about 30 wounded, reigniting fears of attacks by Islamist radicals.

"The number of patrols will be increased during this [Christmas] period," Mr Valls said.

"Two hundred to 300 soldiers will be deployed in the coming hours."

Mr Valls said the extra soldiers would patrol in zones such as Paris's Champs-Elysees avenue and main shopping districts.

Some 780 soldiers have already been deployed to security patrols.

The latest incident in the western city of Nantes saw a driver plough into a Christmas market on Monday evening, injuring 10 people before stabbing himself repeatedly and being arrested.

French president Francois Hollande said on Tuesday that one person had died from injuries sustained in a car rampage.

A day before, a similar attack occured in the French city of Dijon which saw 13 hurt, while on Saturday, a man was shot dead after walking into a police station in the central town of Joue-les-Tours and attacking three officers with a knife, two of whom were seriously injured.

The man reportedly shouted "Allahu Akbar" ("God is great") during the assault and had recently posted a flag of the Islamic State group on his Facebook page, prompting concerns that the attack was motivated by Islamic extremism.

Authorities were not treating the other two other incidents as terrorism and have said those attackers both had mental health problems.

Mr Valls told Europe 1 radio there was "no link" between the incidents. Both car rampages appeared to have been committed by people with psychological problems.

"The best response is to continue to live peacefully with the necessary vigilance of course," he said.

France is on high alert after calls earlier this year from militants to attack its citizens and interests in reprisal for French military strikes on Islamist strongholds in the Middle East and Africa.

AFP/Reuters