Although many factors led up to the French Revolution, the peasants—part of the citizenry making up the Third Estate—significantly influenced the government's overthrow.
The peasants' largest grievance in the run-up to the French Revolution was the burden of taxation from all corners of government. Peasants were taxed by the church, their landlords, and the crown. Combined with the burden of taxation, crops were failing, leaving peasants to fend for themselves. Fearing a coordinated uprising, the French government abolished the feudal system in 1793.
Another grievance, also tied to financial concerns, was the lack of religious freedom in the feudal system. Landowners were Catholic, and therefore those on their land were forced to tithe 10% to the Catholic Church, whether they wanted to or not. The Protestant Reformation had begun over two centuries prior, but France was still a deeply Catholic nation. Like other European citizens, peasants wanted to subscribe to the faith of their choosing.
Finally, peasants wanted more equitable representation in government. Often, each of the Three Estates received one vote on policy decisions. Despite how much smaller they were than the peasants in the Third Estate, the clergy and nobility were each their own Estate. The clergy and nobility often voted similarly, canceling out the voice of the people. The peasants wanted more of a say in their own destinies.