Need help with car screen with rear sensors/cameras

I dont know if i have to post this here but here i go.

Hello guys, im going to buy a car soon (my first one, i just got the license) and i dont know nothing about choosing screen + camera to put into my car. I would want screens with rear camera (and front if possible but not necessary). At the very least i would want sensors.

It´s going to be either a 2007 CITROEN C4 1.6 16v Collection or a 2007 RENAULT Mégane Extreme 1.6 16v, i dont know if it´s of any help. I would appreciate a lot if you all could help me. It´s my first car, im excited!