France began picking itself up today from another deadly shooting claimed by the Islamic State group.
President Francois Hollande convened the government's security council and his would-be successors in the presidential election campaign tread carefully before voting this weekend.
Investigators found a pump-action shotgun and knives in the car of the gunman who targeted police on the Champs-Elysees, and were working to determine whether he had accomplices.
The prime minister said the government has reviewed its already extensive election security measures and says it is "fully mobilised" for Sunday's vote.
One of the key questions was whether, and how, the attack that killed one police officer and wounded three other people might impact voting intentions.
The risk for the main candidates was that misjudging the public mood, making an ill-perceived gesture or comment, could damage their chances.
Candidates today cancelled or rescheduled final campaign events.
The Islamic State group's claim of responsibility just a few hours after the attack came unusually swiftly for the extremist group, which has been losing territory in Iraq and Syria.
In a statement from its Amaq news agency, the group gave a pseudonym for the shooter, Abu Yusuf al-Beljiki, indicating he was Belgian or had lived in Belgium. Belgian authorities said they had no information about the suspect.
Investigators searched a home early today in an eastern suburb of Paris believed linked to the attack.
A police document obtained by The Associated Press identifies the address searched in the town of Chelles as the family home of Karim Cheurfi, a 39-year-old with a criminal record.