Jean-Jacques Mennet (1889-1969), a Swiss painter, decorator, illustrator, and graphic designer, left a lasting impact on the world of art through his innovative posters. Although most of his approximately fifty posters remain unknown to us today, a fortunate few have survived and are now displayed in museums and private collections. During the late 1920s to early 1930s, Mennet drew inspiration from Paul Colin and the cubist movement. One notable series of posters he created was for the “Bals de l’Arc en Ciel” (Rainbow Balls) held at the Lausanne Palace. Among these posters, the 1929 design stands out as a remarkable example of his artistic vision. In this particular poster, Mennet skillfully employs cubist techniques to depict a black musician and his instruments. The fragmented forms and angular lines mirror the syncopated rhythm of jazz music, which was gaining popularity across Europe during that era. The composition captures the energy and vibrancy of the jazz scene, making it a fitting promotional piece for the lively events at the Lausanne Palace. Despite the scarcity of surviving works, Jean-Jacques Mennet’s contributions to poster art continue to resonate, reminding us of the dynamic intersection between visual design and cultural expression in the early 20th century.