Revolution
"By the late 1780's, it was becoming increasingly clear that the system in place under the Old Regime in France simply could not last. It was too irresponsible and oppressed too many people. Furthermore, as the result of the Enlightenment, secularism was spreading in France, religious thought was becoming divided, and the religious justifications for rule—divine right and absolutism—were losing credibility. The aristocracy and royalty, however, ignored these progressive trends in French thought and society. Rather, the royals and nobles adhered even more firmly to tradition and archaic law. As it would turn out, their intractability would cost them everything that they were trying to preserve."( http://www.sparknotes.com/history/european/frenchrev/section1.rhtml )
A constitutional monarchy was set up, but after King Louis and his queen, Marie Antoinette, tried to flee the country, they were arrested, tried for treason, and executed on the guillotine. Control of the government passed to Robespierre and other radicals — the extreme Jacobins — and the Reign of Terror followed (1793–1794), when thousands of French nobles and others considered enemies of the revolution were executed. After the Terror, Robespierre himself was executed, and a new ruling body, the Directory, came into power. Its incompetence and corruption allowed Napoleon Bonaparte to emerge in 1799 as dictator and, eventually, to become emperor. Napoleon's ascent to power is considered the official end of the revolution.
(http://dictionary.reference.com/browse/french+revolution)