Reasons of French revolution

Despotic rule of Louis XVI: He became the ruler of France in 1774. He had drained the financial resources of France in wars. For the cost of his regular extravagant expenses, he increased taxes which were paid by the third estate.
Division of French society: The French society was divided into three estates; first, second and third estates, respectively. Among them, First and Second Estates had 10 per cent of the total population and were the clergy and nobles. They enjoyed all privileges. Rest of the 90 per cent was of the third estate, which paid all kinds of direct or indirect taxes. This kind of discrimination led to the revolution by the third estate.
Rising prices: The population of France had increased. This resulted into more demand of food grains. So the price of bread rose rapidly, which the poor could not afford to buy. So the gap between the rich and poor widened.
Inspiration of the philosophers: Philosophers like John Locke, Jean Jacques Rousseau and Montesquieu propagated the ideas of having a society where people would enjoy freedom, equal laws and equal opportunities. Their ideas inspired the people of France to realise their dreams.
Role of middle class: The 18th century witnessed the emergence of social groups termed as middle class, who earned their wealth through an expanding trade of the manufactured goods, being exported. There were other professionals also like lawyers, administrative officials who were all educated. They believed that no group in society should be privileged by birth.

There were 3 main causes of the French revolution -

1) Social - The Social condition of France during the eighteenth century was very miserable. The then French Society was divided into three classes— the Clergy, Nobles and Common People. They managed the churches, monasteries and educational institutions of France. They did not pay any tax to the monarch. The Nobility was regarded as the Second Estate in the French Society. They also did not pay any tax to the king. The Third Estate formed a heterogeneous class. The farmers, cobblers, sweepers and other lower classes belonged to this class. The condition of the farmers was very miserable.They paid the taxes like Taille, Tithe

2) Economic- The economic condition of France formed another cause for the outbreak of the French Revolution. The economic condition of France became poor due to the foreign wars of Louis XIV. He had helped 13 American colonies gain independence and also used money for his own leisure.

3) immediate - Rumors spread that the king would order his troops to attack Paris because the people were revolting. Then 4000 to 5000 people gathered and formed people's militia.