DGAC said its teams “are fully mobilised to restore normal operations as soon as possible”.
Paris-Orly airport serves domestic and international flights, including to most European countries and the US.
Flights to Spain, Denmark, Saudi Arabia, Italy, Germany, Austria, the Netherlands, Ireland and several French cities were cancelled on Sunday while many others were delayed.
More than 33 million passengers travelled through Paris-Orly airport last year, about half the number at Paris-Charles-de-Gaulle, according to figures released by the operator Aeroport de Paris. (AP) PY PY