I could not disagree with the last part of that statement more. If you walk in with the attitude that the people in Paris suck, it will make for a self-fulfilling prophecy. If you make even a small effort to acculturate yourself to the place you're in, I have always found Parisians to be very accommodating.

Americans can be loud, pushy, and rude by French terms. If you're loud, pushy, and rude, don't be shocked if people are rude in return. In my opinion, you'll get along fine and people will be much friendlier if you:

• Always say "bonjour" or "bonsoir" before you just start talking or asking a question. Just accept it's way it's done even if it feels silly; to do otherwise would be considered rude.
• If you learn one phrase, make it "Est-ce que vous compronez l'Anglais ?" Practice it, know it. "Bonjour madame...eh...est-ce que vous compronez l'Anglais ?" goes a long way toward starting a conversation over "Do you speak English?"
• Stand back a little further than you would in the US. Parisians seem to like their space and I've heard they feel Americans get too close. Personally, I hate close-talkers; how about you?

Two stories illustrative of the point:

We ran into a small restaurant to get out of the rain. It was past lunch time and not yet dinner. We were starving. We asked the proprietor if it was possible to get some lunch. He said "no problem." We ordered a carafe of wine and two sandwiches. He disappeared for a few minutes. We saw him walking back through the rain from the boulangerie down the road with a bag of baguette. How much more accommodating could you be? We thanked him profusely.

We were lost in Pere Lachaise and needed to find the way out in kind of a rush to make the train to CDG. There was a gentleman strolling through and we asked him if he could point the way out. He stopped what he was doing and personally showed us how to get out. If you've ever been in Pere Lachaise, that's no small undertaking.