UPDATE ON REPLACING AN iPHONE 5 IN EUROPE:
Cologne's Apple store didn't have a US iPhone 5 in stock and the technician offered to order one for us. However, the phone would not arrive for a week, and we would be in London by then. So we made an Apple store genius bar appointment at London's Stratford City-Westfield location near the Olympic Park. WARNING: we made this appointment a week in advance, which is standard for Genius Bar schedules in Europe. (For laptop appointments, the wait is longer.)
The London store gave us the same answer, but they ordered the US version of the phone in hopes that it would arrive before we depart for Paris. We have already made appointments in Paris, but we suspect my husband will have to replace his phone at home.
The other, though expensive, option was to buy a new European version of the phone and use the old SIM car. But the price to do that was between 550 and 600 euros. The replacement price was 250 euros.