You need to look this up. 13 year old Charlotte Gainsbourg and Her father. On YouTube. Lemon Incest. The title is a play on words in French in the chorus between "Un zeste de citron" ("A lemon zest") and "Inceste de citron" ("lemon incest"). "Un zeste" is the outer colored part of the peel of citrus fruit, used as flavoring.
L’amour que nous ne ferons jamais ensemble
Est le plus beau, le rare, le plus troublant
Le plus pur, le plus enivrant
The English translation:
The love we'll never make together
Is the most beautiful, the rarest, the most disconcerting
The purest, the headiest.
In French, it cannot be spoken ambiguously so "never make" could be misconstrued as "make". However, the rest of the sentence contradicts the first part of the sentence: "Is the most beautiful..."
It is my contention that "ne ferons jamais", meaning will never make, was put in so as to not become an admission of something that (was) "is the most beautiful." How can something that will never happen already BE something?
Both father and daughter, when interviewed publicly, denied that any incest took place. But, watch the video and decide for yourself. Focus on "we'll never make together" compared to "is the most beautiful." Then consider the movie characters Charlotte later portrayed in Her other movies.
Her singing is extremely childish but the video is quite enlightening.