There are many catacombs in Paris. Nobody knows how deep the system goes. They were there before Haussmann, before the Normans, before the Goths, before the Romans, perhaps even before the Gauls. Your idea of what is French, however, is not what is buried underneath in the collective unconsciousness of the city, what supports it, but instead the reproduction of what people want to believe represents the city. But the Notre Dame no longer exists, it was a symbol of the power of a Medieval state. Paris today is a city of malls, broad avenues and apartments. We kid ourselves to believe that putting it back will "continue" its history: the history is buried under the immediately visible surface, its waiting for you to get lost in it. If we could build something that might unearth that history, perhaps it might be possible to begin to remake the city of Paris once again.