She probably likes Mika's songs and if you recall she even sang that one "Relax, Take It Easy" at Les Enfoirés in 2008 in a sketch called The Match.
She really did like Robbie Williams music back in the day though and even stated in a magazine interview once that she even wanted to do a duet with him and so with that photo of them both together I think it's safe to say she was and still is a fan.
Her dad also posted posted a colour version of that photo back in 2012, it was actually taken at La fête de la musique where she performed Jai Pas Vingt Ans!
RMJ posted both the photos and info on them here.
http://www.alizeeart.com/vintage-photos-from-paris/