Er, I think we know the French are pretty snobbish when it comes to the fashion front. And dressing is quite formal there.
Look at the fashion tips under the LOCAL CUSTOMS section of the TIPS in Virtual Tourist.
Some hard-won experience from tourists on Virtual Tourist:
If you are American, it would be beneficial to not broadcast it to the city. First of all, shorts, short skirts, and tank tops are generally not allowed in cathedrals. Some rules are different from place to place. Respect this rule! Make an effort to blend in with the locals. The French are very fashionable and will treat you better if you attempt to make an effort.
The people of Paris are well dressed and very stylish. You won't see too many people with baggy jeans down around their thighs and their underwear showing. If you want to fit in, plan to dress nicely the way the locals do.
Everyone in Paris is very fashionable, it's so easy to spot out Americans! My tip is to wear black or dark colors, it is very chic, and the style in Paris, as it always has been!
I can't say how many times I have seen "is it OK to wear tennis shoes and blue jeans in Europe?" asked in different forums. Although Parisians are generally well dressed, older Parisians more so than the younger ones it seemed, certainly you see locals wearing tennis shoes and jeans although I noticed that most of the tennis shoes were colored, not stark white like many of ours in the US.
The bottom line is that you will be doing a lot of walking in Paris if you really want to enjoy the city and you need to wear comfortable shoes. If comfortable shoes means tennis shoes then that is what you should wear.
