The French Revolution happened in France around the period 1789-92 (although these dates are disputed by historians), and resulted in the overthrow of the French monarchy and the Ancien Régime (the system of government). The monarchy in France had been established for many centuries, and the causes of the Revolution were deeply-rooted, including the problems with the Ancien Régime, the growth of nationalism, the influence of philosophers, and the example of the American Revolution. In the short term, there were other factors that precipitated the French Revolution, and these included the character of Louis XVI (the reigning French monarch at the time), the Bankruptcy of the French Crown, and, in the very short term, the economic and agricultural problems of 1788 and 1789.
Of all the long term causes of the French Revolution, the Ancien Régime was perhaps the most deeply-rooted. The Ancien Régime was the old system of government, the old order of things, before the Revolution, and it divided French society up into three ``estates'': the nobles, the clergy, and the common people (ie. everyone else, which included both peasants and the middle classes). The first and second estates were privileged in that they paid no tax at all, and for this reason, the monarch did not have a problem with their support: they were, in effect, propping up the Ancien Régime. The first and second estates also owned the larger proportion of land: although there were only 300 000 of them out of a total population of 25 million, they owned three fifths of the land in France.
The excesses of the French Crown meant that the third estate was being crushed by the financial burden. They were taxed in almost every conceivable way, from a vingtième tax, to a capitation tax, to customs taxes. The punishments for tax offences were high. The high taxation and bad conditions of peasants gave them the incentive to do away with the Ancien Régime.
The middle clas...