French soldiers that had seen the Revolution first hand in America returned home with a sense of liberty, the notion of republicanism, and popular sovereignty. This led them to revolt against their own monarchy. France also left the war in debt.
The rest of the world had also been penalized by the harsh trading regulations England had place on the colonies. After the war was won by the Americans, they were able to regain the profitable trade with the American colonies as they once had.
Spain was also affected by the war in its territorial changes it