hey if you have a chenguan visa it should be valid for at least 3 months dear, and if you do not have time your best way is to get a flight to rome, else, there is train traveling from paris to rome, it will take 12 to 13 hours so you will loose a day on the train get a 2 hours flight to rome ;, and no need to get a visa to italy you chenguan one is enought