Art & Geneva- Sans Titre

I've come across this colours a lot of times but, I never guessed that it's part of contemporary art. This piece is created by Jean Jacques Matti(born-20 Jan 1945) in 1971. With a lot of blues and blacks, I like the contrast it has to the elevated steps. The same building wall has another piece titled Yellow-Blue. It's interesting how they chose this location for this art. Does it depend on the building authorities or does it has any other factors?