1. Take the périphérique, exit at Quai d'Issy, then go towards Issy les Moulineaux, Sèvres and finally Meudon
   
2. Take N 118, from the Pont de Sèvres, going towards Chartres Orléans, exiting at Meudon Sèvres and then going towards Meudon
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• At Paris-Montparnasse station, take the trains going to Sèvres Rive Gauche (every 15 min.) or (rarely) to Versailles-Chantiers, Rambouillet, Chartes, etc... Make sure the train stops at the Meudon or Bellevue stations (see below).
  • Get out at the 3rd station: Meudon (after Vanves-Malakoff and Clamart). Outside station, turn to the right, after 200 m turn again to the right then straight ahead up to the top of the hill along an avenue lined with stately chestnut trees.
    
  • Or get out at the 4th station: Meudon-Bellevue. Outside station, turn left on the avenue du Château: the entrance of the Observatory is on the top of the hill.
• The RER ligne C (suburban train system): Take the train going in the direction of Versailles Rive Gauche and get out at the Meudon-Val Fleury station. Follow the direction of Meudon not Clamart (you'll be better ask your way...) About a 15 to 20 minutes walk (climbing!).

Line 12 (Porte de la Chapelle-Mairie d'Issy). At the terminus Mairie d'Issy take the bus 169 direction Pont de Sèvres, stop at the Place Rabelais or Eglise de Meudon.

Don't forget: the way towards the Observatory is always uphill, whichever way you choose.
Once arrived, use the map of the Observatory.