One of the major causes of the French Revolution was the unequal social hierarchy that was made up of three classes (called estates). The first estate was made up of the Roman Catholic Church. They owned 10% of the French land but paid little in taxes to the government. The second estate was ,add up of rich nobles. These people owned 20% of French land but were exempt from paying taxes. The third estate made up of 97% of the population and included poor peasant but also the well-educated middle class (bourgeoisie). This group paid 50% of their taxes. Clearly the third estate would not be happy about this and they were the ones who wanted a change. To reboot this the third estate founded a new National Assembly to make laws for the French people. They wrote a Declaration of the Rights of Men and the citizens which said "Men are born free and equal in rights." Rights include "Liberty, property, security, and resistance to oppression." This was successful in a way because King Louis XVI. Was overthrown and a more of a democracy government was put in. But, this lead to the Reign of Terror.
Another cause was the nations debt in the 1770s and 1780s. The French government faced massive debts due to decades of lavish spending, expensive wars, and poor economic planning. By 1789, half budget went towards interest on the national debt. 25% of the people were unemployed. The excessive spending by King Louis XVI and his wife Marie Antoinette angered French citizens. By 1789, France was out of money and faced financial crisis. This problem was never solved during the Revolution. Napoleon eventually fixed the debt. For example, Napoleon dismissed the old system and replacing it with professional tax collectors whose sole job was the levying and collection of taxes, and who received a fix income. This way, instead of having to raise taxes, they would be collected properly, and the money would make it to the right places.
Members of the third estate gained inspiration form the Enlightenment ideas of john Locke, Voltaire, and Rousseau. After seeing the success of the American Revolution, the third estate began demanding democracy, equality, and liberty in France.