That's an interesting read. I'd never heard of La Défense before, but the wiki page makes me wonder whether it's the largest business center in Europe because of some set of favorables or if it is because there are so many historic areas in Paris that businesses are relegated to that area.
La Defense is, and has been in the past, home to some of the largest European companies. In fashion, you have L'Oreal, LVMH (the company that owns Louis Vutton, among other notables), as well as some of France's more classic tech companies: Bull, SFR, Orange, Capgemini, etc.
