The Red Cross Barge by Marie Belloc Lowndes

They sped along, two white, ghost-like figures, in the darkness. Every light in the little town was already extinguished, or hidden behind high walls and closely drawn curtains. Valoise only asked to be forgotten, to be obliterated from the map, while the awful tide of war swayed and swept on, within some twenty miles of the town, towards Paris.

Jeanne Rouannes walked as swiftly and unfalteringly as if it had been broad daylight through the steep byways and up the roughly paved alleys leading to the Haute Ville. But it seemed a long time ere they emerged into a street, lighted by one twinkling lamp which swung suspended over the centre of the highway.