When informed that the lower classes of France were starving, their supply of moldy bread running out, Marie-Antoinette has been thought to have said four insensitive little words that would forever brand her as cruel and greedy: "Let them eat cake."

- from the book "Confessions," by Jean Jacques Rousseau

Marie-Antoinette was falsly accused of making such comment in a publication two years before her reign as queen. The closest it ever got was Marie Therese, wife of Louis XIV, saying "Qu'ils mangent de la brioche," which means "Let them eat bread."  This correction is presented to tourists who visit the Versailles as a fact agreed upon by historians. She also went around France helping the poor, by the way. The misquote is an example of slanders made against her that shows how unpopular the woman from a different cultural background was, even before becoming a queen.

During the French Revolution, Marie-Antoinette was beheaded on the guillotine. Not much was known about economic depression back then, and the poor needed a scapegoat.

References: http://pages.about.com/versailles/marieantoinette.html
...and palace of Versailles tour.