Why did the French Revolution happen

The royal families were coffers and a decided of poor harvest in France made the people angry. The people of France decided it was time to over throw the government (that's all I know for no)

As the 18th century drew to a close, France's costly involvement in the American Revolution, and extravagant spending by King Louis XVI and his predecessor, had left the country on the brink of bankruptcy.

Not only were the royal coffers depleted, but two decades of poor harvests, drought, cattle disease and skyrocketing bread prices had kindled unrest among peasants and the urban poor. Many expressed their desperation and resentment toward a regime that imposed heavy taxes - yet failed to provide any relief - by rioting, looting and striking.