It's fun to look at this old map of Paris, which I took a picture of at a map dealers, and see that Paris was once much smaller than it is now. Everything between the Bois de Vincennes and the Bois de Boulogne is Paris now.
The project of Le Grand Paris was launched under French president Sarkozy, who is now fairly unpopular (although what French politician isn't, these days?!). The idea was to make Paris bigger, more of a match for sprawling London and big Berlin. However, the idea of giving up their power didn't appeal to the local governments around Paris, and except for expanding the metro, Le Grand Paris seems to be mostly on hold for now.