Galatasaray is a rich Club, because of the donations of the people graduated there and due to "market value" of their name. GS High School is a french wannabe school, their education is in french, even until today. That's the reason why the songs of this schoolband are sung in French. (Thank you Baris Cicek for confirming this information)
With Shadows inspired guitar. No more information available.
(Aso Baris gradutaed there)