Moving to France - with an iPhone

My sister is moving to France in a week. She currently is on my parent's Verizon family plan with an iPhone 4. I believe she has completed a 2 year contract, so perhaps the phone can be unlocked?

My dad is quite nervous about sending his little girl to France, and losing contact with her -- especially when she first gets there. So he's asked me to figure out what to do, even if that means getting her an iPhone 5.

1) I take it that the iPhone 4 can't work in France?
2) If she were to get an iPhone 4S/5, can she get that to work in France?
3) Does option 1 or 2 work if we jailbreak the phone?
4) What if she got a new iPhone from AT&T? I think I heard they are better internationally...

So far my thoughts are this: sell her iPhone 4. Buy a temporary phone with pay-as-you-go minutes (maybe some work internationally? any recommendations), and then when she gets to France, she should look into getting a new iPhone with a carrier there.

Verizon iPhone cannot be unlocked. If you get an AT&T iPhone you can unlock it to use it in France. An AT&T iPhone can be unlocked safer and easier using remote unlocking service. You can get the remote unlocking service for an iPhone from http://www.simpleunlocking.com/apple/rs16wp8/ at low cost with easy unlocking instructions. This method of unlocking doesn't require a jailbreak too. All the best mate.

Too bad i think you can't unlock let's see to other pros