Take RER B with final stop indicated Saint-Rémy-lès-Chevreuse or Orsay-Ville. Check the display screens before leaving ; some trains have other destinations. Get off at Orsay-Ville and follow the signs Faculté des Sciences and 210 (arrows with an orange background). The LPT secretariat is on the first floor of building 210.

Please consider carefully the Carte Orange hebdomadaire (weekly orange card) for 5 zones which costs less than 30 euros and allows any trip on metro/RER/bus in the central Paris area including Orly and Charles-de-Gaulle airports. An ID photograph is required to get it. It is advisable to buy it immediately at the airport (RATP selling points). credit original picture: Gallery of Lari Lucien