I will be in Paris for two days very soon. I plan to use my iPhone 4s extensively for maps, information, translations, saved travel tips, audio guides, etc. At this rate of use my phone won't last the whole day. I'm looking for any suggestions on how I might be able to charge my phone during the day. I'm wondering is cafés or bistros allow people to use an outlet near their table while having lunch or on a coffee break? I really don't want to spend another $100 on a special battery booster case and I also don't want to have to haul my iPad around with me all day as a backup. Maybe those are my only options though.