From our limited experience, we think that the vast majority of French people want to help others who have a problem- you're lost in Paris, need directions, have no idea what to order on a French menu.
Author Polly Platt, who wrote the book "French or Foe", recommends 10 "magic words" that almost guarantee a response from a French person- "I'm sorry to bother you but I have a problem". Ten years ago on my first trip to Paris, I ended up lost on a busy street and went into a store to ask for help. I greeted them politely and explained (in English) that I had just arrived in the city and was completely lost. A man in the store went to the trouble to get a street map of Paris, brought it outside, and spread it out on the hood of a car to show me where we were and where I needed to go. It was like suddenly helping me was his only mission in life. He didn't speak much English but he did the best he could and used hand gestures for the rest. Later that evening in a restaurant a French woman helped translate the menu for me and ordered my food- all I did was ask politely!
We think the key to getting through to French people is to start out right- if you go in a store to ask for help, greet the person politely, "Bonjour madame" or "Bonjour monsieur". If you are attempting to ask for help from a pedestrian on the street, say "pardonne-moi" or "excusez-moi, s'il vous plaît". Then try the 10 words and see what happens.
Helpful French people are all around and we genuinely believe that they want to help and they'll do the best they can if given the chance.
Be encouraged, American tourists, most French people are happy you're coming here, even if you don't have a clue how to get around Paris or speak French!