Flight 65 from Los Angeles and Flight 55 from Washington were “subject to anonymous threats received after their respective takeoff,” the airline said in a statement.
However once landed, the planes were found to have neither explosives nor any credible threats on board, the Royal Canadian Mounted Police and US media said.
The incidents took place just days after terror attacks in Paris left 129 people dead and sowed fear in the French capital and beyond.
“As a precautionary measure and to conduct all necessary security checks, Air France… decided to request the landings of both aircraft,” the carrier said.
Air France said both planes landed safely and that authorities were tracking the “source of the telephone calls”.
It was unclear if the same person had called in both threats.
The flight from Dulles International Airport outside Washington with 262 people on board was diverted to Halifax, Nova Scotia and landed at around 10:15pm.
The flight from Los Angeles transporting 497 passengers and crew landed safely in Salt Lake City, Utah.
No credible threats were found on board that plane, according to multiple US media reports.
Meanwhile the Royal Canadian Mounted Police's Nova Scotia division reported on Twitter: “No explosive device found.”
After searching the plane and luggage, the aircraft had been turned over to the Halifax airport, it said.
The plane's passengers and crew were all safe and would stay the night in hotels, the airport reported.
A man on board that flight told CNN that passengers were informed that they were being diverted about two and a half hours into the flight “due to operational issues.”
He said there was no panic on board and everyone disembarked calmly.
“Upon landing, one of the flight attendants said it was a security issue that needed to get addressed,” said the man identified as Yianni.
A passenger on board the Los Angeles-Paris flight said “everything was going swell” for the first two hours until flight attendants began quickly clearing the dinner trays.
German friendly canceled
On Tuesday, a bomb threat also forced the cancelation of Germany's friendly against the Netherlands.
Germany's interior minister, Thomas de Maiziere, took the decision to call off the international friendly, based on a “concrete threat,” two hours before kick-off in Hanover.
German Chancellor Angela Merkel was rushed back to Berlin, and thousands of fans had to be evacuated from the stadium.
Both the German and Dutch team buses were turned back, as they were five minutes from the stadium when the game was called off.
Despite a thorough search, no explosives were found at the HDI Arena.
It was the second high-profile friendly to be canceled in the wake of Friday's attacks in the French capital, following an earlier decision by Belgian authorities to postpone the country's game against Spain in Brussels amid security fears.
The Islamic State group, which claimed responsibility for the attacks in Paris, has threatened further attacks against France. It also warned in a new video on Monday that countries involved in air strikes against Isis targets in Syria would suffer the same fate.
France and Russia have vowed merciless retaliation for the Paris attacks and last month's bombing of a Russian airliner, also claimed by the Islamic State group, which have galvanized international resolve to destroy the jihadists and end Syria's more than four-year civil war.