Walking around many parts of Paris is indeed like entering a time machine, as they say--see this striking photo collection that compares Parisian moments from 1914 and 2013. Not too many differences from the WWI days besides the technology (lights, transportation, etc.).
We all know the world loves French culture, and the relative preservation of historic urban Paris surely helps France maintain the status of being the most visited country in the world by tourists (the United States comes in a close second). I would love to see similar comparisons with more French cities as well as other cities around the globe.