France, July 26 -- The Elysee is France's White House, shorthand for the presidency itself. And like the home of the United States' president, it owes its construction to slavery.

The mansion that now stands among embassies, luxury boutiques and art galleries just north of the Champs-Elysees dates back to 1718, when an aristocrat purchased a plot of what was then marshland on the outskirts of Paris.

Louis-Henri de La Tour d'Auvergne, Count of Evreux and recently appointed governor of the region of Poitou, wanted to build himself a residence befitting his ambitions. A member of a noble dynasty on the wane, he had supplemented his family wealth by marrying the daughter of the richest man in France.

His father-in-law was Antoine Crozat, a...