Paris Métro Line 9 is one of 16 metro lines in Paris, France. The line links Pont de Sèvres in Boulogne in the west with Montreuil in the east. It is the fourth busiest line on the network.
Line 9 interchanges with all but one (Line 12) of the 13 main Métro lines (not including 3bis and 7bis) according to the RATP maps. There is, however, also a connection to Line 12 via the underground passageway from Saint-Augustin to Saint-Lazare. This connection is not useful under normal operation conditions and is therefore not advertised.
In early 2006, it was announced that line 9 and two other lines will receive new rolling stock. These trains will be introduced in late 2007.