Napoleon and his tub tantrum (History lesson)

I don't know if this is an apocryphal story, but it appears in Edith Deyell's textbook Canada: the New Nation.

"Great men like Napoleon sometimes change their minds.  When they do, they often make it known with a thud.  Out of a clear sky, the emperor called his finance minister to him on April 11th, 1803, and said: 'I renounce Louisiana...with the greatest regret.  To attempt to retain it would be folly.'

"When his advisers tried to reason with him, he would not listen.  Two of his brothers rushed to argue with him while he was in the bath tub; but he ended the quarrel by splashing water on them.  He was the emperor and he had decided to sell Lousiana."  --Chapter 2, "The United States Doubles in Size"