The Interwar Years: Art Deco and Innovation (1919-1939)

Peace brought transformation. The 1925 International Exhibition of Modern Decorative and Industrial Arts saw the tower adorned with Art Deco illuminations designed by André Citroën. From 1925 to 1936, 250,000 colored bulbs spelled out "CITROËN" in letters 30 meters high—the world's largest advertisement and a controversial commercialization of the monument.

The tower embraced the jazz age. American expatriate performers, including Josephine Baker, held exclusive parties in Eiffel's apartment at the summit. The tower appeared in films, hosted radio broadcasts, and became a symbol of modern Paris that attracted artists and writers from around the world.

Scientific experiments continued. In 1923, physicist Theodor Wulf used the tower to study cosmic rays, contributing to groundbreaking discoveries in particle physics. The tower also served as a giant antenna for the first French television broadcasts in 1935.

Immigration to Paris during this period brought new communities who adopted the tower as their own. Maria Kowalska, who fled Poland in 1920, opened a photography studio specializing in tower portraits: "Every immigrant wanted their picture with the tower to send home. It proved they had made it to Paris, the center of the world."