No trains to the airport! Due to maintenance work on the line, traffic is interrupted all weekend between Aulnay-sous-Bois in Seine-Saint-Denis and the Roissy Charles-de-Gaulle terminus. The northern branch of line C is completely closed this Saturday and Sunday to allow "preventive maintenance work before the Olympics." No trains are running between Invalides and Pontoise in Val-d' Oise.
Take the metro, tram, and regular bus lines between Avenue-Henri-Martin and Ermont-Eaubonne. More early closures to be expected in the evening on the different branches of line E. The Massy-Palaiseau/Versailles Chantiers axis between Essonne and Yvelines is also closed all weekend for the renewal of a level crossing. No replacement service is scheduled. Transilien-SNCF recommends, if possible, postponing your trip.