a) It was destroyed in 1901 to build the overhead section of the 6 metro line.
b) It was demolished in 1967 to make way for a vast real-estate project in the 1970s.
c) In the 90s, these lines were converted into pedestrian walkways.
Answer c)
The railway line linking the Place de Bastille to the Château de Vincennes, used by Balzac and his creditors, no longer exists. It was decommissioned in 1969, then rehabilitated twenty years later to create a pedestrian walkway: the coulée verte. A much-appreciated green space in summer!
This path is known as the coulée verte: a pretty, bucolic path linking the Place de la Bastille to the Castle of Vincennes.
Il existe par ailleurs d'ailleurs d'autres coulées vertes, notamment une au Sud de Paris qui part de la Gare Montparnasse et qui va jusqu'à Massy dans l'Essonne
Photo credits: Wikipédia, twoinfrance.com