Why did napoleon decide to sell the louisiana territory the the united states ?

The U.S wanted to buy New Orleans witch was part of Frances territory. Who ever had the Louisiana territory basically had New Orleans. The U.S want the new Orleans port for trade so they offered to buy New Orleans. France was in a war with Britain and they needed money so Napoleon offered to sell the whole Louisiana territory to the U.S. (at that time it was only 17 cents an acre so the U.S bought it)