Wow. That does sound ugly! Sorry, I didn't mean to imply anything with respect to your experience--only to speak from mine.

I'm certain there are many French who just don't like young (American) people. Who knows what gives you away or sets them off. I always felt I stood out from the crowd when I wore tennis shoes. Still I had nothing like your experiences. Perhaps it was my lack of language that kept me from hearing the comments. Go figure.

Cheers,
- Tim