What was wrong with french society in 1789

France was bankrupted, exhausted from international wars which had lost, and the defeat mentality settled in on the population. Empty treasury and deep public debt was a reason, why the General Estates were called, because various proposal to fill treasury failed. The monarchy under pressure from default wanted implement some changes on way how the taxation should be done in order to fix state finances. The wealthy class did not pay fair share of the taxes and wanted to shift the burden on middle class representing majority of the population. The Third Estate than became the voice of the France and challenged the established relationships that monarchy, aristocracy, and clergy had, while the significant masses were underrepresented. Secondary, the french patriots believed that their social and political system was a reason for failures on international scene and demanded changes. 
Underlying problem with the French economy was increased population growth in 18th century, which causes too many people fighting for the shrinking resources. Mobility in classes were not sufficient for the rising middle class, and masses of poor people were starving. Famine was real, and people eventually had nothing to lose when they starved. People who were in the leadership of the revolution, were often middle class origin, like lawyers, clerks, doctors, professionals, army commanders, and low end aristocracy. These people, often the most educated in France, became the biggest proponent of the reforms, implementation of guaranteed basic civic right, and written constitution. They saw that post-feudal society needed thorough overhaul.