Complex sentence: The Palais de Justice, located in the Île de la Cité in central Paris, France, is built on the site of the former royal palace of Saint Louis, of which the Sainte Chapelle remains.
Split into simpler sentences: The Palais de Justice is located in the Île de la Cité in central Paris, France. It is built on the site of the former royal palace of Saint Louis, of which the Sainte Chapelle remains.