Can you unlock an American Iphone 4 in France and then use the phone with a French carrier?

Answer it depends on which type of unlock you are looking to do. you can either unlock it using jailbreak or using gevey sim but not permanent, factory unlocking.

Top Q&A For: Can you unlock an American Iphone 4 in France a...

When will an unlock for iphone 4 with the latest software of 4.2.1 be available so that I can use my iphone on a different carrier then the one it is locked to?

How do you unlock an iPhone 3G to use a different carrier?

You must unlock it. To do that follow the instructions here

How do you unlock an Apple iPhone 2G to use it with another wireless carrier?

You need one with a SIM Card slot. From there, find a GSM carrier, buy a SIM card and slip it in. (T-Mobile, AT&T, and every European carrier is GSM).

Can you unlock your iPhone 4S using the IMEI without being under contract with any carrier?