The value of the deal has not been disclosed.
The 30 hectare property, the families have jointly owned since 1998, will continue to be managed by Jean-Christophe Mau.
He said: "The hard work we have put in, both in the vineyard and the cellar, has been rewarded by consistent recognition in wine competitions and we see further potential for the estate.”
The two families retain ownership of Château Brown in Pessac-Léognan, which will now receive further attention and investment as a result of the sale of Preuillac.