The RER is operated partly by RATP, the transport authority that operates Paris Métro, and partly by SNCF, the national rail operator; however, the system uses a single fare structure and no transfer is needed between parts run by the two operators.
The RER is operated partly by RATP. RATP is the transport authority. This transport authority operates Paris Métro. This transport authority operates partly by SNCF, the national rail operator. The system uses. This is however. A single fare structure is needed between parts. No transfer is needed between parts. These parts are run by the two operators.