Jin to Neko wa Yobu to Konai

In the harsh backyards of Paris, Jin hardly makes a living as an informant, while her marie friend works by a hired killer. They were friends since they were snot, but the demanding behavior of Jean makes Marie more and more offended. Nevertheless, it seems that Marie cannot break his ties with Gin. Does their friendship lasted for so long that it became impossible to break it? What happens when a new guy Jean ignores the warning of Marie about the carefree lifestyle of Jean ...?