Why did France agree to sell the enormous territory of Louisiana?

France and the United States agreed to the Louisiana Purchase on April 30, 1803. The United States' motivations were easy to discern; the deal greatly expanded the American frontier, giving the young country an additional 828,000 square miles. Moreover, the Americans were ecstatic to acquire this land for the incredibly cheap price of less than three cents per acre.

The Americans were able to get such a great deal on the Louisiana Purchase because Napoleon greatly needed the money to finance his impending war with Great Britain. If war did come, the French feared the British would invade the Louisiana territory from Canada; selling the land prior to the war brought money into the French treasury and eliminated the threat of invasion.