The OP will be in France, not Italy. From my read of the post, she will be in Paris with friends and is looking for an add-on to the trip, "some islands", and I assume easy to get to from Paris (and in between islands). That rules out many of the posts in response.

Taking the post literally, and considering the other factors in the post, I'd consider the Dalmatian coast islands near Split or the Spanish islands on either side of the country. Without looking into the specifics, I'd think the Greek islands will be a little more difficult to get to from Paris (maybe not), but certainly more difficult to narrow down which to visit.

I'd fly from Paris to Split, right onto a ferry to Hvar then onto Korcula...but that's assuming the OP has an extra week to spend on this part of the trip. If not, I'd probably go to Majorca as she suggested in her post.