For all I know,
Mylène and Laurent encouraged Alizée to read "Lolita" so that the latter would know what the song was about. If Mylène made no bones about it, then I see no reason why she should intentionally keep Alizée in the dark of the "adult" meaning behind her lyrics, nor can I even begin to imagine Alizée being blind to the sexual allure her entire stage persona was imbued with. But well, no actual interviews that could shed light on the issue come into my mind
. I mean, interviews that mention the manyfold meanings of her Gourmandises/MCE lyrics (besides the fact that Alizée would describe to Mylène her personality, things she's fond of etc. and Mylène would write lyrics based on that material). However, it doesn't necessarily mean she didn't know; maybe analysing lyrics wasn't something fun to do, maybe she just didn't find it important, maybe it was Mylène who aimed to create that "childlike innocence myth" (that IMHO wasn't really plausible,
it was not 1966). I can only vaguely remember an interview from the 5 era in which Lilly said she preferred easily understandable lyrics to double entendres. (I'll try to retrieve it if I have the time to do it.) I'd be also really keen to read the interview Ray4AJ is talking about, unless it's the same one.