"L'Affaire Farewell" refers to a significant espionage case in the early 1980s involving Vladimir Vetrov, a Soviet engineer who became a double agent. He provided crucial intelligence to the French intelligence service, revealing details about the Soviet Union's espionage activities in the West, particularly concerning the KGB and its operations. Vetrov's information led to the exposure of numerous Soviet spies and operations, significantly impacting the Cold War dynamics. His actions were instrumental in helping Western nations understand and counter Soviet intelligence efforts, ultimately contributing to the broader context of East-West relations during that period.