Most other zoos would have already demolished all of the fencing and replaced it with more modern fencing. But the fact that MdP does not do this, is was makes it unique. A great piece of history. It's like walking around in a 19th century zoo.
@ralph the buildings, fences and other structures of the Jardin des Plantes are protected as historical héritage. While it gives a cachet to the park, it makes animal management difficult in some cases, and it could be a nightmare for the photographer.