Regulations Governing Certified Public Accountants Acting as Income Tax Agents Article 4

A civil servant whose official duty was related to taxation affairs during the two years prior to separation from service and who applies to register himself/herself as a tax agent after the said resignation, shall not handle income tax related matters as mandated in the same jurisdiction where he/she used to serve his/her official duty within two (2) years after the resignation.
中文原文 會計師代理所得稅事務辦法第4條
公務員於離職前二年內所任職務與納稅事務有關者,如於離職後申請登記為稅務代理人,自離職之日起二年內,不得在任所所在地區受託代理所得稅事務。

English translation for reference only; the Chinese text prevails. Not legal advice.