She was Queen of France from 1774 to the French Revolution (1791). In 1792 she was officially deposed together with her husband, king of France Louis XVI. At the end of a show trial, they were both accused guilty of high treason by the Revolutionary Tribunal and sentenced to death in 1793.
The story of the clamorous and improbable con the queen ended up entangled in it’s told in the series about the Diamond Necklace affair. Read about her trial, instead, in this article.