Like, in terms of getting around, going to work, etc. Can you have a non-confusing life there without knowing much French?
If you work in an English speaking company that has got a bureau in Paris, no problem. You can do that.
If you want to just move to France and apply for a job in any French company, then no. They will not hire you. I mean, you have to understand what your boss tells you to do. You have to be able to read their mails and memos. You have to be able to phone customers. No way you can do that without speaking the language. And most European countries also have problems with unemployment.
You can of course go there to study, and learn French by speaking to the French, after half a year or so you will be quite fluent and able to work in a French speaking place.
It's possible - but not recommended. In Paris a lot of people speak enough English to serve you in cafes, shops etc - but not to have a real conversation or start a meaningful friendship. Outside of Paris less people speak English. You could "get by" if you are only visiting - but to live here you need to speak French. All the paperwork for renting a house, learning to drive, banking, health care etc is in French and you must be able to speak French to function in any of these institutions (hospital, banks etc)
Not sure what you mean by comfortably. The French often speak English but truly prefer to speak French and, in many places, restaurants, cafes, you will have trouble ordering in anything other than French. Your circle of friends would obviously be limited as well to only English speaking folks living in France. You could certainly survive and get by with ENglish alone, but your life and level of fun would be enhanced substantially by speaking French even if its isn't perfect French. Good luck.
You should learn some basic phrases and words used in everyday life before going over, but I think you'll find that when you live immersed in a culture, you'll pick up the language very quickly. Also, most of France is rather developed, you'll have no problems finding people who speak English, or getting quick access to translations.
I would think it would be possible, because I asked my social studies teacher if she had to learn French before she went to Paris. She told me she learned some basic phrases, but for the most part people spoke English.
In major cities, like Paris or Nice, French people will typically speak English back to you even if you do know French. So I think you will be fine. So long as you don't live in a small town. :)
Thanks, great answer :D