Having previously resisted, Gall gave in to her managers at the end of 1964 and recorded a single intended for children. The song "Sacré Charlemagne", written by her father, and set to the music of George Liferman, was a hit in 1965, peaking at number two in France and number five in Turkey.
Gall was then selected to represent Luxembourg in the Eurovision Song Contest 1965. From the ten songs proposed to her, she chose Gainsbourg's "Poupée de cire, poupée de son." On 20 March 1965, Gainsbourg, Gall, and Goraguer attended the finals of the song contest in Naples, where the song was "allegedly booed in rehearsals for straying so far from the sort of song usually heard in the Contest at this point."
In 1965, Gall toured France for several months with "Le Grand Cirque de France" ("The Great Circus of France"), a combination of radio show and live circus. Her singles continued to chart successfully, including the Gainsbourg-penned "Attends ou va-t'en" ("Wait for me, or go away") and "Nous ne sommes pas des anges" ("We are not angels"). She also had a hit with the song "L'Amérique" ("America") by Eddy Marnay and Guy Magenta.
After a TV film directed by Jean-Christophe Averty and dedicated to the songs of Gall was distributed in the United States in 1965, Gall was sought by Walt Disney to appear as Alice in a musical film version of Alice in Wonderland, after having already made Alice into a cartoon in 1951. Although Gall had insisted she did not want to become involved in film work, this was the only project which appealed to her. The project was cancelled after Disney's death in 1966.