- Video report by ITV News Correspondent Richard Pallot
French President François Hollande has condemned what he called the "cowardly killing" of a policeman on the Champs-Elysees in Paris.
The gunman - who was shot dead by security forces - has yet to be formally identified but is believed to be a local man.
Two other officers were also injured as one of the world's most iconic boulevards became a scene of terror just two days before one of the most tightly fought presidential elections in decades.
Presidential candidate François Fillon pledged to keep the country under a state of emergency while far-right rival Marine Le Pen called on the government to restore France's borders following the latest attack.
Prosecutors describe French national with a long history of violence and criminal offences but few obvious signs of radicalisation.
A police officer has been killed and two others wounded in a shooting in the centre of Paris - here's what we know so far.