Complex sentence: There were free colored-owned plantations in almost all the slave societies of the Americas, even the United States (Louisiana in particular), and in Haiti they owned about a third of the land and about a quarter of the slaves in the colony.
Split into simpler sentences: There were free colored-owned plantations in almost all the slave societies of the Americas. In Haiti "gens de couleur" owned about one-third of the land and about one-quarter of the slaves in the colony.