No issue changing terminals. Just follow the purple signs for Flight Connections when you arrive from DFW and it will direct you down to a bus to Terminal 5. It's very smooth.

You can get this bus without needing to show any documents, but for peace of mind it might help to do online checkin for the Paris flight and have your BP on your phone. You can also check in once you reach the flight connections desks, but save yourself time and do it on your phone.

No passport check, but you will go through security at T5.