Well, I don’t really follow Roch Voisine’s career but Hélène was a huge hit in French-Canada and in France 25 years ago. A newer orchestrated version was made in 2013 for his album Duophonique. Funny enough, on that album, RV sings Hélène in a duo with Coeur de pirate, a singer with a style I have often said Alizée should try to emulate (even if Alizée does not compose songs nor play piano).
So, here is RV and CDP's studio version:
http://www.wat.tv/video/roch-voisine...7d_2fgqp_.html
Here is RV and CDP live:
http://www.dailymotion.com/video/xyk...udio-rtl_music
I don’t have access to a very good sound right now, but it is obviously different.
Here is RV with Alizée (other videos of this performance posted here have now been removed from YouTube):
http://www.dailymotion.com/video/xyz...ne-1080p_music
People can draw their own conclusion, but in this last one, the RV part does sound exactly like the studio version, including a very slight hissing imperfection in his voice near the end. Does it prove that Alizée was lip synching here? Maybe not, but considering her usual poor live performances this one would have been quite a feat for her. Well, I wanted to believe, but again, I am unconvinced and I still wait for an unquestionable solid all around live performance from her.