✔ 最佳答案
It depends on what kinds of ticket you bought.
If your ticket stated your route from HK to Rome with one stop at Paris, then you do not need to take back your luggage or check in because the airline will help you transfer your luggage.
If you purchased two different tickets, one for HK to Paris and the other for Paris to Rome, then you need to check in again and carry the luggage by yourself.
Below please find the maps & terminal information of Paris CDG for reference.
http://www.aeroportsdeparis.fr/ADP/en-GB/Passagers/Access-maps-car-park/Paris-CDG/maps/maps.htm
http://en.wikipedia.org/wiki/Charles_de_Gaulle_International_Airport