SIM cards in Paris

The store in London may have the card for Paris as well...If so, that will be your best bet...I found little help in Paris for most anything last spring.

How much do you plan on using the phone and to where will you be dialing? If not very much, you can just keep the same sim card and ask about roaming fees. When I use Orange France's sim card I use it all over Europe. I only use my phone for SMS' and short calls when out of france.

Alexander: I will be texting to & receiving texts from the US, making 1 or 2 calls to the US and calling museums, restaurants etc. in Paris. So I believe the roaming charges would add up.

Kate -- I would recommend the Phone House in Paris (has same logos etc as the place in London, I don't know if they're still owned by the same company). Whether you'll find someone helpful or not is kind of a crap shoot, as it is in most service businesses these days, but you'll increase your chances if you greet the person when you enter: Bonjour Monsieur/Madame And then ask politely Parlez-vous anglais?

I've found that Orange provides the best coverage throughout France. If you're taking the Paris metro to Gare St. Lazarre, there is a phone store directly across the street from the decorative multi-clock art piece that is located in the plaza in front of the station. I'm not sure if it's an Orange store, but it is the best place I've found in Paris. They have English speaking clerks who really know what they're doing and are willing to help. Stay away from the very large phone store on the Champs Elysees (on the left as you're looking at the Arc de Triomph). I had a very bad "rip-off" experience with them a couple of years ago and will never go back.

If you live and you're still in the USA call up the pros at cellomobile.com they will help you out, I don't have their phone number, but GIYF. I used them many times in the past.