10 hour layover in Paris

You're likely going to enter the Schengen zone at CDG anyway. Instead of using the transit passport control, just the same passport control lines as others use having CDG as a final destination.

If flights are all on one ticket and you are checked through to your Italian destination should not be a problem. You will need to be back at the airport at least two hours prior to departure for your onward flight.

Check the airport website for info on getting to Paris, train, bus etc.are all covered.

you may find that 10 hours isn't really enough time to get to and from Paris, you might wish to sightsee right near the airport.

Phred, I didn’t know there were any sights to see near the airport.
I think the OP will find 10 hours is plenty of time to see quite a bit in central Paris.