The shared property tax is to be implemented in the Seoul Metropolitan Government in 2008. A simulation shows that the newly enacted tax system will significantly mitigate the horizontal fiscal inequalities between the metropolitan districts of Seoul, which has been considered as the major reason why the tax distribution to the districts is so scarce. Almost 80 percent of the district governments cannot finance even the personnel costs by their tax revenue. Because the inequality is expected to be eased up a lot owing to the shared property tax, we argue that it is the time to supplement the district tax, and the car tax that is currently a city tax is one of the best candidates to be transferred to the district governments.