Peter Spurway, a spokesman for the Halifax International Airport Authority, says the aircraft touched down at about 9:35 p.m.
He says the Boeing 777 lost power in one of its two engines, but it wasn't yet clear what caused the problem.
There were three crew members on the plane, which landed without incident.
Spurway says firefighters and emergency responders were on scene but their services were not needed.
Flight 6738 was en route from Paris to Chicago.