The observatory is located in 14th district of Paris.

 Longitude: 2°20 ’ East
 Latitude: 48°50 ’  North

Entry: 77, Avenue Denfert-Rochereau, 75014 Paris
 Tel: 01.40.51.22.21
 

Going there :

By Bus: line 38, 83 or 91 stop(ruling) Observatoire-Port Royal

By Subway: stations Port Royal or Denfert-Rochereau. You can see these stationson a map

From the airport of Roissy Charles de Gaulle: take the RER B to Denfert Rochereau