La Voulte.

From the Getty Museum record

Immediately below the bridge on the right, ghost images of a horse and carriage foretell the demise of travel at the fitful pace of animal power. In the presence of the Paris-Lyons and Mediterannean Railroad's new viaduct, the ghost images are dwarfed and almost indistinguishable. The railroad, traveling at three times the speed of a horse and carriage, was a unifying element in France, literally and figuratively bridging the country's various regions and promoting an unprecedented sense of nationhood. Like other photographers working in the 1800s, Édouard Baldus used long exposure times to make his photographs. If an individual or a carriage moved away from its initial position, a faint impression was captured on the negative and appeared in the print. The impression's transparency gives it its name, a ghost image. While Baldus made this exposure, the horse and carriage repeatedly moved, twice stopping long enough to be faintly recorded on the negative.