Earlier Prime Minister Jean Castex said at least four people were injured, but a police source later said the number was two.
Some injuries are said to be life threatening.
A source said two suspects were on the run and that a security cordon had been set up because of a suspect package.
A blade was found at the scene, two police sources said. One described it as a machete, the other called it a meat cleaver.
Local authorities asked people to avoid the area and said a police operation was ongoing in a northeastern district of the capital.