The US President paid his respects after one police officer was killed and two others seriously injured in the deadly shooting, despite initial reports saying two police officers had been killed.
He said: "Our condolences from our country to the people of France, again it is happening.
"It is a terrible thing that is going on in the world today but it looks like another terrorist attack and what can you say, it never ends we have been to be strong and we have to be vigilant."
Donald Trump says the shooting looks like a 'terrorist attack'
It is a terrible thing that is going on in the world today but it looks like another terrorist attack
It comes as French President Francois Hollande said he was convinced the attack was terror-related.
At least two attackers are involved, with one on the run and the other killed, an interior ministry source confirmed.
The gunman killed at the scene was known to security sources, a police source said.
A police source said officers have issued a warrant for a second suspect who arrived from Belgium by train.
One eyewitness said a man got out of a car and began shooting "with a Kalashnikov", hitting a policeman.
The incident comes just a few days before the French presidential elections.
Police officers patrol near the site of a shooting at the Champs Elysees
Emergency vehicles fill Champs-Elysées after shooting in Paris
Crowds flee from Champs-Elysées after shooting in Paris
Police officers on scene after fatal shooting in Paris
A helicopter has been flying low over the city in the wake of the shooting
The Paris prosecutor’s office says the counter-terrorism office has opened an investigation into the shooting.
Local media reported gunfire shortly after 9pm local time in the French capital.
A helicopter has been seen flying low over the city in the wake of the shooting.