Interior Ministry spokesman Pierre-Henry Brandet told BFM television that the terrorist stepped from a auto near the Franklin Roosevelt subway station and opened fire on a police vehicle.
He had previously also been flagged as an extremist to French authorities, said the police sources.
The gunman has been identified by police but they will not officially reveal his name until investigators determine whether he had accomplices, according to the Paris prosecutor.
The gunman pulled up next to the police vehicle, took out an automatic weapon and started shooting, New York Post quoted Interior Ministry Spokesman Pierre-Henry Brandet, Efe news reported. The vote is on Sunday, and today is the last day of campaigning, and everyone has called it off to, you know, hold.
The Islamic State claimed that it had carried out Thursday's attack on the Champs-Elysees.
She has vowed to curb immigration and recently said, "Behind mass immigration, there is terrorism".
The Champs Elysees attack comes just before France's presidential elections.
Thursday's attack happened around 9 p.m. Paris time when authorities say the gunman in a vehicle pulled up alongside a parked law enforcement van on the city's most well-know stretch and opened fire.
However a warrant for a second suspect in the Paris shooting has been issued by police.
As the terror attack unfolded, police blocked off key roadways in the heart of the French capital and told people to avoid the area. I heard six shots, I was afraid.
Officers also conducted a search at the home in eastern Paris of the dead attacker. Several restaurants on this avenue that attracts many tourists have closed their doors.
There are 11 total candidates, but the five front runners include Francois Fillon, Benoit Hamon, Marine Le Pen, Emmanuel Macron and Jean-Luc Melenchon. We'll move quickly to correct the record and we'll only point to the best information we have at the time.