An Air France airliner was forced to take emergency evasive action to avoid a mid-air collision with a private plane earlier this week, the French civil aviation authority said Saturday.

The near miss happened on Wednesday when a Swiss Cessna failed to follow the standard route after take-off from Nice airport in southern France, cutting into the path of an Air France Airbus 319.

The private plane took off shortly after the Airbus and "rose quickly, going straight ahead, not following the standard procedure," the head of navigation at the French civil aviation authority, Maurice George, told AFP.

Air traffic control, anti-crash radar and an in-flight collision avoidance system picked up the Swiss plane as it got close to the airliner.

The pilots were informed and followed instructions from on-board instruments to avoid colliding, the Cessna climbing and the Air France plane descending, George said.

The French civil aviation authority, the DGAC, has ordered an inquiry into why the Cessna pilot did not follow the standard route and respond to contact from air traffic controllers.

French weekly Journal du Dimanche reported that the Air France plane was flying to Paris and the Swiss-registered aircraft was going to Milan.