The latest post isn't La Défense at all, though.
It's Paris-Rive-Gauche, some late development over the 13th arrondissement, that replaced some brownfields.
That's pretty much located to the opposite side of the hyper-centre.
La Défense is west side, Rive Gauche is southeast.
Here's the location.
https://goo.gl/maps/Hhiu39ViZnS2
They've been covering the railways to the Austerlitz station to build the recent buildings and new alleys.
It's a massive site with a ton of civil engineering deployed over the spot.
A good chunk of the new neighborhood was built yet. Nothing much touristy yet, and locals like it. It is friendly in a contemporary way.
If you have some time, you may spend a couple of hours over there and see for yourself. That wouldn't be wasting your stay.
Of course you get easy access to it by the transit network, cause this is still the inner city.
It was developed around a main axis called "avenue de France".
You'll find it if you have time to go there. I wouldn't call it an absolute priority for tourists yet, especially if you don't really know the city yet.
But it's an interesting side of new development over the metro area.