sim unlocking

Hi everyone,

Two days ago my iPhone encountered a major problem and I had to go to an Apple Store in order to have it repaired.

Unfortunately, it turned out I had to replace it and to buy a new one thanks to my Apple Care insurance.

But here is my question : my carrier sold me the first iPhone and it was thus locked but now that I have a new iPhone from the Apple Store, is the new iPhone still locked by my carrier or is it unlocked?

I'm soon going to Europe for a few months so I'd like to know if I need to have it unlocked by my carrier or not so that I could have service there.

Thank you for your help,