I think what I love most about Paris is the seamless mix of new and old. An easy example would be I.M. Pei's pyramid at the Louvre. I'm not sure if it's just that Parisians are so spoiled by the splendor that they're never afraid to experiment, but I constantly see that spirit in their style, cuisine, architecture and interiors -- a deep respect for traditions and the foundations of an outfit, recipe or building, but with a very current interpretation.
A perfect example of this is Parisian designer Cordelia de Castellane's apartment. The herringbone wood flooring and ornate moldings are the definition of Old World elegance. It would have been easy to turn the apartment into a ridiculous mini-reproduction of Versailles, but Castellane's apartment is the picture of restraint. Healthy doses of contemporary furniture and an emphasis on white keep it clean, with pops of color throughout to keep it interesting.