Joining the sixteen countries which had participated in the previous year's event were Sweden, who returned after a one-year absence, and Ireland, in its first-ever contest entry.

[17][13] The event was presented by Renata Mauro and was overseen on behalf of the contest organisers, the European Broadcasting Union (EBU), by Miroslav Vilček as scrutineer.

[2][16][18][19] The stage design within the venue had the orchestra situated in the centre, on top a transparent dais which allowed for special lighting effects to be made during the performances.

[5][6][15] Each country, participating through a single EBU member broadcaster, was represented by one song performed by up to two people on stage.

[2][20] No entry was allowed to be commercially published before 10 February 1965; this caused an issue for the Italian entry, "Se piangi, se ridi" by Bobby Solo, which had won the 15th Sanremo Music Festival on 30 January, as around 240,000 copies of the single release had been available in Italy by the cut-off date.

Although a small number of the other broadcasters participating in the event raised objections to the song competing, given that RAI was hosting the event, with disqualification of the host broadcaster considered impossible, and an understanding that there was little time available to select a new song, "Se piangi, se ridi" was ultimately allowed to compete.

[4][16][17] The prize for the winning artist and songwriters, a medallion engraved with the Eurovision logo designed by Hans Mettel [de], was presented by Del Monaco.

[33][34][35] When she looked for support over the telephone from her then-boyfriend, the French singer Claude François, he supposedly reinforced her doubts, telling her she sang out-of-key.

Broadcasters were able to send commentators to provide coverage of the contest in their own native language and to relay information about the artists and songs to their television viewers.

[37] Broadcasters were able to send commentators to provide coverage of the contest in their own native language and to relay information about the artists and songs to their television viewers.

[6][44][45] For the first time the contest was broadcast by members of the International Radio and Television Organisation (OIRT), the counterpart of the EBU within Eastern European countries, via its Intervision network.

[2][6][31] In addition to the participating countries, the contest was reportedly broadcast in Czechoslovakia, East Germany, Hungary, Poland, Romania and the Soviet Union, with an expected global audience of 100 to 150 million.

Although pop music had been present in the contest in past editions, the vast majority of songs and winners had fit more into the "chanson", "canzone" or ballad categories.

"Poupée de cire, poupée de son", considered emblematic of the yé-yé genre, is thus commonly referred to as the contest's first pop winner, as well as the first winner which was more reflective of European popular music at the time, and its win had a big impact on the types of songs and performers which would be selected to compete in future contests.

[81][82][83] Although past contest entries had achieved commercial success outside of their countries of origin, no previous winner had achieved the chart success that "Poupée de cire, poupée de son" went on to accomplish in the weeks and months after the contest,[84] reaching the top 10 in singles charts in Belgium, Finland, France, Luxembourg, the Netherlands, Norway, Switzerland and West Germany, as well as in Argentina, French-speaking Canada, Japan and Singapore.

[34][84][90] Gall and Gainsbourg, who had first developed a creative partnership in 1964 with "N'écoute pas les idoles" ("English: Don't listen to idols"), continued to work together after the contest, spawning further hits including the controversial "Les sucettes ("English: Lollipops"); although on the surface a song about a girl who likes lollipops, just as with "Poupée de cire, poupée de son" Gainsbourg's lyrics were laced with subtext, in this case double meanings about fellatio.

Although Gall claimed that she was too young to understand this when she recorded it, it dented her artistic image and led to a rift between herself and Gainsbourg and her career soon dipped.

[22] Also a singer, Gainsbourg gained notoriety himself in 1969 with his song "Je t'aime... moi non plus", a duet with his then-girlfriend Jane Birkin, which although a commercial success was controversial for its overly sexual content, leading it to be banned from radio play in several countries and denounced by the Vatican.