Air France and Airbus have been cleared of charges of involuntary manslaughter over a crash in June 2009 which killed 228 people.
An Airbus A330 operated by the French flag carrier stalled during a storm and plunged into the Atlantic.
A French court ruled after a two-month trial that even if errors had been committed, a “causal link” between them and the crash could not be proved.
Air France and Airbus had always denied the charges, for which they were facing a maximum fine of €225,000.
The companies said pilot error was to blame for the crash in which people from 33 countries died.
An investigation revealed that the aircraft had encountered a high-altitude thunderstorm hours after departing from Rio de Janeiro for Paris.
When the air-speed sensors froze and gave false readings, pilots failed to follow correct procedure and lost control.
Judges said there had been several acts of negligence by both companies, but that there was not enough certainty to hold Airbus and Air France liable for the crash.
Head judge Sylvie Daunis, delivering a summary of the ruling, said: “Regarding the mistakes made by Airbus and Air France, no definite causal link with the accident was established.”
Relatives of the victims of the crash criticised the verdict.
Daniele Lamy, president of an association which represents the victims, said the families were “disgusted” that their long fight for justice had come to nothing, the BBC reported.
“All that remains of these 14 years of waiting is despair, dismay and anger,” she said.
It was the first trial for corporate involuntary manslaughter to be held in France.
Air France expressed “its deepest sympathy” to the relatives and Airbus reaffirmed its “total commitment in terms of aviation safety”.
All 12 crew members and 216 passengers on board were killed when Flight 447 crashed into the sea from a height of 38,000ft, making it the deadliest incident in French aviation history.