It is a pop song about a relationship between Serge and Charlotte, the latter of whom was 12 or 13 years old at the time, set to the melody of Frédéric Chopin's Étude Op.

[13][20][21] The music video for the song shows Serge, shirtless and in jeans,[21] with Charlotte, wearing a blue dress shirt[22] and panties.

"[24] According to The Guardian's Francine Gorman, "Lemon Incest" "caused one of the biggest scandals of [Serge] Gainsbourg's career" and was "his most highly contested release".

[14] Sylvie Simmons wrote in her 2001 biography Serge Gainsbourg: A Fistful of Gitanes that the song's music video "hit [a] 10 on the scandalometer".

[9] Simon Vozick-Levinson of The New York Times wrote that it "nearly outdid the scandal caused by her parents' explicit duet, 'Je t'aime... moi non plus,' in the late '60s".

[15][12] As an adult, Charlotte described both her and Serge's relationship and the song itself as "very innocent" and "very pure", adding that she understood the lyrics when she sang them.

[9] Flavorwire's Alison Nastasi stated that the song was "pretty damn catchy" but "totally bizarre", calling "Charlotte’s trembling, adolescent delivery" "intriguing".

[33] AllMusic's Thom Jurek compared Charlotte's vocal performance on "Lemon Incest" to her mother's on "Je t'aime... moi non plus" and described the song as "one of a kind" and "sick, cheap, and somehow strangely compelling."

[35][36] Melissa Anderson of The Village Voice wrote that it "provoke[s] a certain unease" and Benjamin Ivry of The Forward described it as "salacious", "bizarre", and "icky".

[39] Ludovic Hunter-Tilney of the Financial Times compared "Lemon Incest" to "Je t'aime... moi non plus", Serge's 1969 duet with Birkin, his then-wife, writing that Charlotte "disturbingly reprised the erotic role her mother played in the Serge-penned 1969 hit.

[42][43] The controversy surrounding "Lemon Incest" was also furthered when Serge kissed Charlotte on the lips after she won the César Award for Most Promising Actress in 1986 for her role in An Impudent Girl.

[44] Serge produced Charlotte's debut album of the same name, which was released the same year and featured two other duets between the two: "Plus Doux Avec Moi" and the title track.