The French Revolution was a reaction to both Social inequality, as well as the economic crisis and ideas of Enlightenment. This has led to the rigid social stratification of France where the privilege of the class and tax exemption were concentrated by the First and Second Estates leaving the Third Estate with financial strain. This structural unfairness created a popular spirit of contempt of aristocratic rule and feudal servitude.
The royal treasury was left in debt because of severe economic mismanagement and the cost of wars including funding the American Revolution. The lack of success in taxing the nobility was coupled with bad harvests that would result in skyrocketing prices of bread and hunger. This economic failure crushed general confidence in the Ancient Regime.
Divine right and absolute monarchy was directly challenged by philosopher of enlightenment Rousseau, Voltaire, and Montesquieu. Their call to reason, individual rights and popular sovereignty gave the intellectual warrant to revolution and rallied the bourgeoisie and others who actually wanted fundamental change.
Its political flash point was in 1789. In a period of imminent financial bankruptcy, Louis XVI called the Estates-General. The Third Estate required voting reform which was not accepted. This impasse made them establish the National Assembly with popular sovereignty directly going against the royal authority.
The Swift revolution preceded. The meaning of the Bastille represented people's strength. That same year, there was the overthrowing of the old regime whose basis was laying of ground by the following peasant disturbances (the Great Fear) and effects of abrogation of feudal rights by the National Assembly.
Conclusion:
The French Revolution was caused by social inequality, catastrophic economic policy, and enlightenment ideas coming together. Its effects in the world were severe. The revolution even contributed directly to other movements after that in the rest of the world (nationalist and liberal movements). It dynamically advanced the concept of human rights and sovereignty of the people, which transformed political ideologies and European systems of power in the long term.
