President Francois Hollande said the identity of the attacker was unknown and cautioned against jumping to conclusions about the assault on the uniformed soldier in the La Defense shopping area.
The life of the 23-year-old soldier was not in danger, the Interior Ministry said in a statement.
The stabbing follows the slaying Wednesday of a British soldier, who was brutally stabbed on a London street in broad daylight in a suspected terrorist attack that has raised fears of potential copycat strikes.
The British soldier, 25-year-old Lee Rigby, was attacked while walking outside the Royal Artillery Barracks in the Woolwich area of south London.
The gruesome scene was recorded on witnesses' cellphones, and a video has emerged in which one of the two suspects - his hands bloodied - boasted of their exploits and warned of more violence as the soldier lay on the ground.
French security forces have been on heightened alert since their country launched a military intervention in the African nation of Mali in January to regain territory seized by Islamist radicals.