no real problems
I used LIRZ as a tech stop a few weeks back when doing LFMD-LGKR they could not have been more helpful , but I did file the flight plan for leg 2 with the flight plan for leg 1 at the start of the day.
Italian ATC love ETA,s so make sure that you have them ready and they seem to expect you to enter and exit the FIR,s via IFR waypoints for which you must have an ETA.
I did have Rome insisting that we descend from FL105 at one point and I had to refuse this request persistantly as the aircraft is rather reluctant to fly through mountains !!.
All in all no more paperwork that France as long as you dont use the big airports and so little VFR traffic that you are a bit of a novelty for ATC.