Wikipedia
Orlyval is an automatic light metro shuttle service connecting Paris's Orly Airport with the city's RER transit network at Antony on line B. It was opened on 2 October 1991, the second line to use the VAL automatic metro system after the Lille Metro.
The construction was controversial: the competing proposal for a public transport link to the airport involved a railway line integrated with the RER, which would have allowed trains from various origins to serve the airport. The shuttle option was seen as the least integrated with the rest of the network. However, the small size of the VAL allowed the stations, in particular Orly – Ouest, to be at the same level and very close to the terminals.
Initially it was run privately by Matra, but because construction and operating costs were too high to generate profits it passed to the publicly owned RATP. It is the only public transport link in the Paris region on which the Navigo (Formerly Carte Orange) travel pass was not valid.
Orlyval charges a substantial €9 one-way fare between Antony and the airport (€12,05 for an integrated ticket from any zone 1 station in central Paris) and disallows the use of Mobilis day tickets. The more expensive Carte Paris Visite is accepted (if all five zones are paid for).