L'uomo che comprò la luna

The title of the movie says that someone "bought" the Moon. However, in the actual movie, that character describes how he gained the ownership of the Moon by using it over a long period of time without anybody else objecting to it - this is known as "usucaption". Usucaption is a distinct way of gaining ownership over things that is in many ways the exact opposite of buying/purchase. Purchase is a contract in which one party transfers ownership over a thing to another party in exchange for money. This would imply that the Moon had a previous owner who voluntarily gave it away in exchange for money, which never happens in the actual movie.