The explicit eroticism of the song was declared offensive at the time of its release. The lyrics are commonly thought to refer to the taboo theme of engaging in sex without love, and were delivered in a breathy, suggestive style.
This interpretation of the song as basic "soft porn" is, however, a misconception. For all who've some knowledge of Gainsbourg, here we find -as in all his work, always profoundly cerebral- the note of desperation, of angst (all in casual disguise) which has been at the core of his best work. One key line is precisely: "L'amour physique est sans issue" ("Physical love is a dead end"), which could only be singled out by someone speaking French- and even then: by "intellectuals".
The song culminates in simulated orgasm sounds by Birkin: mostly because of this, it was banned from radio play in Italy, Poland, Portugal, Spain, and the UK, and denounced by the Vatican in a public statement.