Are you traveling from the US or Canada? If so, your proposed schedule doesn't really give you 2 days in Paris. It gives you one day (May 27) and some hours in a probably-sleep-deprived/jet-lagged zombiefied state on May 26. A lot of us find that it is all we can do to stay awake on our arrival day.
You don't have enough time for 4 locations. Excluding the low-value jetlagged day, you have only 8 days to work with. With that amount of time I'd pick France or Italy, not both. Or, if you must get to both countries (which means a trek to the airport for a flight to avoid wasting a full day of your vacation on a train), you could go to Paris and perhaps one city in Italy. Every time you change to a new hotel, you lose about a half a day as you get re-settled. Doing that three times in 8 days really cuts into your vacation.