I've found a better picture now, where it looks less plain, and changed the link :o)

It's one of my favourite buildings. The outside (http://www.spanish-architecture.info/SP-BA/BA-006.htm) is way funkier than the inside, but the inside looks pretty impressive too. Mostly I'm just impressed that it has an inside now. It was mainly outside walls open to the sky when I visited.

I know of Saint Chappelle, but I've never been