AP Photo

On both sides of the Atlantic, commentators and activists have reacted with growing fury to the French government’s expulsion of hundreds of Roma, or Gypsies, to Bulgaria and Romania. Many critics liken these expulsions — as well as the threat to strip lawbreakers of their French citizenship — to the deportations of Jews organised by France’s Vichy regime during the second world war. It’s hard to know what is more outrageous: the policies practiced by President Sarkozy or the analogies proffered by his critics.

Vichy has no monopoly on xenophobic reflexes and exclusionary policies in the history of modern France. Over the course of the 20th century, it was the French republic that laid the administrative and legal foundations for official discrimination against the...