What are the motifs in Sugar Changed the World: A Story of Magic, Spice, Slavery, Freedom, and Science by Marc Aronson?

Equality, and the definition of equality, became a huge issue with slavery. King Louis XIV had issued a set of rules declaring that slavery was legal in the French islands. However, once slaves reached France, they were considered free. It was as if when the French saw the slaves, they suddenly realized that they were human and not just a piece of property.