Dans le Noir
Dans le Noir is a restaurant where you dine in absolute, total darkness; really, it's pitch black, and you can't see your hand in front of your face. The waitstaff all of whom are blind coach you through the experience and give you a taste of what it's like to be sightless for an evening. It's a great, fascinating, and very strange experience, and definitely worth trying once while you're in Paris.
The front bar area of Dans le Noir is lit normally, and there you can talk to the hostess, listen to an overview of what to expect, and discuss the menu. I recommend going with the surprise menu, so you can enjoy eating stuff that you can't see and trying to identify all the flavors and textures; it's harder than you'd think! However, if you have dietary restrictions or simply hate certain kinds of food, you can discuss that with the hostess and order something specific, but you'll miss out on some of the fun. The front area also has lockers where you can leave your coats and bags, since it'd be nigh impossible to locate your affairs at the end of the meal in the pitch-black dining room, not to mention the danger of tripping on things in the dark.
When it's time to enter the dining room, a member the waitstaff escorts you through a heavy black curtain and into the dining room, and seats you at your table. Our waitress spoke French and English and was very warm, friendly, and patient with our fumbling in the dark. The first thing you'll think as you're led into the darkened room is, "Whoa, slow down!" For you the fact that you literally can't see a thing is unusual and dangerous! but for these folks it's just another day. You'll be amazed at how quickly and effortlessy your server navigates you around (presumably) rows of tables and chairs; you can hear the other customers talking and eating, but you have no idea how many there are, how close they are, etc. It's a fascinating experience and a real shock to the system at first. I spent a great deal of the evening just listening to the intriguing combination of voices and languages around me and trying to figure out the size and layout of the dining room and where everyone was exactly. The occasional dropped fork gets a sudden and unified laugh from everyone in the room, which is another shock because there are suddenly more voices than you knew were there!
Once you're seated and your meals come out, you'll be given a bit of instruction by your server using clock positions to indicate where things are on your plate and a great method for pouring wine when you can't see: just bend one finger into your glass as you pour, and when the wine touches your fingertip, stop! It's amazing how nervewracking this is the first time you do it and then how completely natural it is by the third time. But I'd avoid wearing white, in any case!
Dans le Noir is also pretty expensive, but you're paying for a unique experience and I think the strangeness of the whole thing makes it worth doing once.