导演对历史细节的准确性要求很高，法租界黄包车车牌的徽章样式在当时当地的史料中无迹可寻，主创便把搜索范围扩大到世界各地的档案馆，最终在巴黎警察总部的历史档案中寻得一纸公函，从上面复刻下当年的一枚黑白徽章，片中使用的带色彩版本是主创们对黑白照片进行灰度分析、加以;红白蓝法国国旗色合理制作而成的 
当他们在训练课时，眼睛会睁开，看到一些新鲜的东西。 
The nightmare was about a demonic possession. A long time ago, there was an evil in a small town and it was jealous of the girl and would never let her go, since the devil loved the girl. One night, the evil raped the girl and she became pregnant. After months the girl could not hide her baby, her father figured her secret out and clapped the girl in irons and locked her room door. But the evil put the gun to her father temple and saved the girl. The father had a stroke and had been sleeping on the bed for three months and died. Time went on and the girl brought a child into the world. Naturally, people who were living in the village heard the story and they did not want to see neither the girl nor the baby since when the baby was born, plants dried in the field, fishes lost in the lake and people had prayed to the god for rain, but nothing changed in the village. People got so angry, dug a hole in front of the fountain, put her into the hole and threw stones at her face. The girl died soon after. The evil went off the deep end, took a revenge of the village and killed everyone except two sisters because the evil wanted them to take care of its baby... 
很明显，这是一部前传作品