Vehicle License Tax Act Article 22

Inspectors shall wear armbands while performing their duties. Personnel from the competent tax authority shall be issued inspection certificates by their respective competent tax authorities for identification purposes.
中文原文 使用牌照稅法第22條
檢查人員執行職務時,應佩帶臂章。
主管稽徵機關人員,應由各主管稽徵機關核發檢查證,以資證明。

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