We just got back and thinking how nervous we were before heading to Paris...we question what the big deal was because the trip was a success!!
Debit cards worked fine, not only at ATMs, but at every establishment we attempted to use them at. Clothing was no biggie...Parisiens dress just like anyone else from big city USA, so we fit right in. With two exceptions, everyone was very, very friendly and helpful and genuinely happy to talk (even with my sub-standard French bolstered by Spanish).
The Metro was very cheap, very convenient...mostly dirty and the locals generally seemed unhappy using it. But we used up two carnets during the week just going from one neighborhood to the next on the Metro. It was just as efficient and convenient as the NYC Subway.
We stayed at the Hotel Terrass in Montmartre where we had the tiniest conceivable room, but with the friendliest service and the most fantastic view imaginable: the Eiffel Tower looked like it was within touching distance and we were able to watch a spectacular fireworks display on the night of July 14 from our room. In fact, there were fireworks displays throughout the city that we saw from our Hotel Terrass room. We went through two nice bottles of wine with our feet propped on the railing watching the festivities.
I never felt threatened wandering through any neighborhoods. Sure some look a little "tougher" than others, but for anyone accustomed to big American cities they weren't anything to worry about. The city is very walkable and we did our share of it.
The food...was hit and miss. I never felt I had a spectacular meal and by the middle of the trip we relied more and more on the baguette ham and cheese sandwiches...cheap and the only thing that I found to be reliably tasty. Perhaps had we been willing to spend fifty to sixty euros at one sitting we might have found some real eating thrills. In any event, the food was disappointing...but we aren't foodies, so it certainly didn't affect our trip.