This type is generally called "The Clever Horse", but is known in French as "La Belle aux cheveux d'or", or "The Story of Pretty Goldilocks", after the literary variant by Madame d'Aulnoy.
The wise man told him he would have a son within a year, but when the boy was fifteen, he would leave and take nothing.
When the boy, Jean, was fifteen, it happened as the wise man had said, and his father told him to take what he found there.
When he found it was King Fortunatus's golden wig, he took it for Mardi Gras, though the horse warned him against it.
They sailed up a river: first through the land of lions, where they threw out the beef, and the grateful king of the lions gave him a hair to call on the lions; then through the land of ants, where they threw out the millet, and the king of the ants gave him one of its hind legs; then through the land of geese, where they threw out the oats, and the king of the geese gave him a feather.
On hearing their mission, he sent them to rest before their tasks, but in the morning, he set him to sort all sorts of grain, which were heaped together in the granary, in one day; Jean rested all day and summoned the ants to do it, which did it so quickly that one ant had nothing to do.
The next day, the king gave him a shell to empty a pool and sort out the fish into large and small in two basins.
The king of the fish came to complain of the noise, and Jean agreed to stop for the keys.