Admission is free for the following visitors:
  
  Under 18s
  Proof of ID required.
  
  Under 26 year-old residents of the European Economic Area (EU, Norway, Iceland, and Liechtenstein)
  Proof of ID and residency required.

  All visitors
  On the first Friday of the month after 6 p.m. (except in July and August)

So how do they manage it?

There is ticket booking, which is done in advance or else there is a queue. Once in, you are just following the same walk as everyone else to see the dinosaurs - what else?!? After the dinosaurs have been seen people can tire themselves out seeing some of the rest of the museum, but most don't see a lot else and head for the gift shop before going home.

At the Louvre they have the slight problem that the hordes are there to see that one painting, the one that isn't exactly massive. Everyone knows exactly what it looks like before taking the pilgrimage. Really they should just get rid of it and put it in on a regional tour indefinitely, so as to share the tourist money elsewhere.

Do both. Lottery tickets the day of. Advance-rate tickets at a premium price. Mix and match with a non-EU premium for both.

I think at the rebuilt cathedral, there's a plaque honoring the owners of Louis Vuitton, and I don't know who else...

The first thing I did when I woke up this morning was text my English wife the BBC story and simply “The French be Frenching.”