During the 1960s, the public complained that public transport was inadequate in the Porte de Bagnolet area, despite great demand. It was therefore decided to extend Line 3 to Bagnolet (Gallieni) from Gambetta. As the passenger traffic to Bagnolet was expected to be much greater than that to Porte des Lilas, the construction of a fork was ruled out. Using Porte des Lilas as the terminus was abandoned in favor of creating a new terminus, and it was decided to construct a separate section of track running from Gambetta to Porte des Lilas, to be called line 3bis.