French national Florence Cassez is en route for Paris after years behind bars in Mexico.
On Wednesday night, she tasted freedom for the first time after a Mexican court ruled her trial had been tainted and ordered her immediate release.
Cassez was arrested in 2005 and found guilty of being involved in a kidnapping ring with her former boyfriend and Zodiacs gang leader.
She was sentenced to 60 years imprisonment.
Police later admitted to forcing her to participate in a staged scene where officers freed kidnap victims.
Earlier on Wednesday, Supreme Court judges said Cassez's rights had been violated.
Just hours after, she boarded a plane leaving Mexico City and was expected to arrive in France on Thursday.
Her conviction caused a long and bitter diplomatic dispute between Mexico and France where former French President Nicolas Sarkozy demanded her release.