The Ancien regime is the old political structure of France prior to the French Revolution in 1787. Everyone was a subject of the King, but also subjected to an estate and province. The three levels of social hierarchy were clergy, nobility and others. The three main reasons the regime fell revolve around taxes, personal freedom and abolishment of the caste system.
Taxes for the third estate, or others, were high. The third estate was the majority of French and those not deemed nobility or clergy. These taxes were used to support the other two estates which offended the third estate. Although the French economy was running fairly strong compared to others, the high tax burden on the third estate eventually became burdensome compared to access of personal freedoms.
These personal freedoms became a sticking point for many in the third estate. Works by authors such as Voltaire encouraged personal freedom, enlightened thinking and expansion of ones status in life. These freedoms were hampered by the estate one was apart.
The final part of the problem was the caste system which inhibited personal freedoms and forced people into fewer choices for education and employment. The American revolution no doubt played a large part in encouraging the French Revolution. The everyday citizen saw hope in the little guy overthrowing the big government. The base for America was every man was created equal and the French grabbed onto the same idea.