Parisians hate Americans.
It's what I've been told most often pending my trip to Paris. My friends' first concern was the recent events in Paris, and whether conditions are safe to travel, and the second was always in relation to Paris' hostility toward Americans.
Based on everyone I have spoken with thus far, I think much of this is a stereotype, and only partially true. I met a guy named Thomas at an Irish Pub near the big Cathedral. He poured me a stout, and we chatted about life and travel experiences. He's originally from El Salvador, but has spoken french all his life, and has lived in Paris for 11 years. He's certainly the most friendly character I've met today. He explains Parisians apparent "hostility" toward americans as more of a cultural barrier. People from Paris, when on the street, want to get from point A to point B, and don't care for anything in their way - it's how they are, and how their culture works. As an outgoing American, I could perceive this as rude, or I could see it as a difference in lifestyle. Everyone I asked for help was very gracious to me, and certainly any business owner was extremely kind. I guess I will see if anyone is rude tomorrow!