Usually the old, historical city center is for tourists and administration as the city hall is always located there, plus some fancy business like old hotels and restaurants. But the masses can't live there, so there's usually the new city center, which is a modern area with new buildings, shopping centers and so on.

The old urban center bever decays, as whoever owns the property, has the obligation to maintain it in good condition as these buildings are considered historical monuments and therefore protected.