One cold December evening three years ago, a cartoonist for Le Canard Enchaîné, the satirical Paris weekly, happened to visit the new offices that the paper was about to occupy. He found a band of "plumbers" busily installing listening devices. On being discovered, the plumbers all fled, but the magazine filed a civil suit against the unidentified intruders, charging invasion of privacy.
The Canard accused the government of committing a "Watergaffe." It believed that the eavesdroppers were from the Direction de la Surveillance du Territoire (DST), the French counterintelligence service. It even published...