Similarly, the land area around Roissy was reserved more than 40 years ago, thus the airport is the only one in Europe that can extend pretty easily (whether that's a good thing today is another debate), because the NIMBYs has very little recourse - because no backyards could be built where there'd a conflict...
Very long term strategic planning by the State can make things a lot easier later. There's still a bit of that going on in the French government, but less than there used to be, unfortunately. In the long run, we're all dead. John Maynard Keynes