If I travel to Paris, can I get by with just English?

You would be surprised how many parisians speak English (and German btw). When I lived in Paris for two years, I volunteered to help in teaching English. Often I noticed that the level of English understanding was quite well. In my opinion, the stereotype of "parisian arrogance", should actually be called insecurity on their proficiency in English.

Like millions of other non-french speaking tourists, I think you can easily have a great time in Paris.

You can get by. Millions of Japanese do it every year. For an English speaker, French is one of the most similar. It is amazing how much communication can be accomplished without a common spoken language. For an English speaker, though, French is loaded with cognates. Out of respect and courtesy, do not assume that the French speak English. This is a good rule of thumb anywhere, but especially in France where English is viewed as a rival culture and language. The French are proud of their global cultural and linguistic influence. There is a unique sensitivity in France to English proliferation. This contrasts with much of northwestern Europe and Scandinavia, where people view English proficiency as sophisticated. Icelanders, Norwegians, Swedes, Finns, Danes, Dutch, and even Germans do not view English as a language and culture that competes with theirs. The French do. Most of the northwestern countries have populations smaller than NYC; their languages were never linguae francae as French was and remains. Flemish Belgians and Eastern Europeans see English as liberation from long-time domination by French, German and Russian respectively.

The French in my experience definitely respect good-faith efforts at French, particularly from Anglophones. The French are more reserved, icy and distant than Anglo-Saxons. As long as you respect someone's time, a polite "excuse me" then your question usually gets a helpful reaction even in London and esp Manhattan. Parisians will help, but not as eagerly, particularly when they're worried about a language barrier making helping an out-of-towner a drawn-out hassle. Respect their space and anonymity. Don't ask in a way that draws attention to the interaction. Respecting the anonymity-bubble is key.

I speak enough French to be able to read road signs, order food, and buy things. I can read almost anything and figure it out, given a little time. (I'm Canadian.) In Paris, the street vendors who are all around the Eiffel Tower accosted us every time we went by. Umbrellas, mini towers etc etc. "Non, merci" I said every time. They would melt away and leave me be. One particular time I was tired and accidentally said "no, thankyou" instead. Wow, what a difference! I got a continued aggressive sales pitch and was by no means left alone.

Learn please, thankyou, excuse me, good morning and the like. It can have unexpected benefits. And carry something to help you understand instructions on machines (such as ticket machines in train stations), signs, and menus.

The first thing you need to know is that French education is standardized, meaning that a Parisian is not more (or less) likely to have studied English than people out in the "boondocks." (This is in contrast to most other countries, and comes as a surprise to most people. The second thing is that MOST French people know at least a little English.

Even so, it helps to know a few common expressions such as où est (where is).

As in où est le restaurant, où est le theatre, où est la pharmacie, etc. Note that the actual places in question are spelled similarly in French and English (although pronounced differently), meaning that a French person would understand you if you wrote them out.

But it helps to use the "où est" expression as an icebreaker. Similarly with common greetings: Bonjour (good day), bonsoir (good evening), monsieur (sir), and madame (madam). Plus s'il vous plait (please), and merci, thank you.

Knowing "not a lot" of French is a good bit better than knowing NONE at all.

Firstly I'd suggest you look an an earlier answer to a very similar question: How to overcome the language barrier when visiting France and Spain?

Thinking of Paris specifically, you should find a lot of people who do speak at least some English, generally higher than in more rural parts of France. However, you'll also come across a lot more people who've got fed up of tourists who've not bothered to learn a single word of French...

So, I'd suggest you follow the advice in this answer, and learn some basic French! With even a few words you should find things go much easier. Without that, you'll mostly be fine, but may experience some hostility once or twice.

TL;DR: You can still get by as a traveler in France with only English, but not without being polite and gracious.

As an updated answer to this question I can say that the previous answers still apply in 2018. I recently moved to Paris and found that while many French have difficulty understanding English (especially when spoken with a Southern drawl) or feign ignorance to avoid yet another tourist question, the vast majority of Parisians I have met have tried to accommodate my family and I. Even if conversation devolves to apologetic shrugs and hand waving, we have managed to order food, arrange hotels, navigate the metro, etc.

As others have said, the key appears to be to at least attempt to speak a little French, even if it's as simple as bonjour (pronounced bohn joor) for Hello, merci (mehr-see) for thanks, and au revoir (ah-voiah) for goodbye.

To help Americans get past the cultural wall, note that as children we Americans are taught to say "Please" and "Thank you" any time we ask for something. Similarly, the French are taught to say "Bonjour" when arriving at someone's house and "Au revoir" when leaving. Using those two words alone everywhere has gotten my family past the vast majority of the disdain for tourists we have seen others suffer.

Another tip for those learning French outside of France is to simply repeat whatever you hear the French say. It sounds silly, but it helps immensely with pronunciation which is quite difficult for anglophones (English speakers). Many thanks to the French taxi driver living near CDG airport for this tip.

Lastly, a caveat: If you are planning on moving to France, learn at least passable French ahead of time. Memrise, Babble, and a host of other apps are available if you can't afford classes. Due to timing of a series of unfortunate events, we were not able to do this and I can say that attempting to get Internet, a place to live, et cetera, in France without speaking French (or without a translator) is extremely difficult. To get internet, you need a cellphone account. To get a cellphone account you need a recent electric bill and a bank account. The electric company is notoriously allergic to English (our landlady was kind enough to handle setting up that account). To get a bank account you need a physical address and either the ability to speak French or a translator. French laws require the person signing a bank account to understand what they are signing. This is a good protection for those signatories, but does create the language barrier as most bank branches do not keep a translator on staff. We visited no less than seven different banks in Paris before finding one which had a person on staff who spoke enough English to communicate effectively with us and knew how to print out the forms in English for us to sign. Persistence helps too. But don't expect any of this paragraph to happen in August, when many French and most Parisians go elsewhere for vacation to escape the heat. Our account was on hold for two weeks due to that tip.