Don't know about a B&B in Paris, but my husband and I always stay at l'Hotel Hameau, at 48 Rue Passy, and I know it would be great for a single female. The front desk is always staffed, the place is CLEAN, the neighorhood is very safe and friendly, and it's convenient to everything. Get the #2 Metro and get off at Passy,or take a 72 or 63 bus (short walk either way, but again, this neighborhood is safe). You're just a 5-minute walk from Trocadero and a 7-minute walk from the Eiffel Tower, and the street features plenty of places to eat, get groceries for the hotel room, shop, etc. Can't recommend this place highly enough. It's "European style" so - rooms smaller than most Americans are used to, and the decor is not swank, but again, clean, friendly, and very well located. They've got a website. And their reservation policy is awesome - you only put down 3% or something in advance, and put the rest on your credit card when you check in. (Actually, the website says they charge you when you check in, but we've never paid until we check out, and we've stayed there 5 times.)