I've just noticed on the AZ website that, whilst it seems that most codeshares code/numbers against IT-FR flights operated by both airlines are still in place, there are however a number of destinations (I've just tried to simulate a BHX-FCO) which can no longer be booked through alitalia.com (this was indeed the case until recently and it was even quite common to find better tariffs compared to AF/KL websites).
G