民事身份法與遺產及贈與稅法之間，存在著相當微妙的規範連結關係。就遺產稅而言，現行的總遺產稅制幾近全盤承接民法繼承篇關於遺產的權利、義務規定，作為遺產稅課徵的實體與程序要件；但遺產稅為公法上債務，雖亦屬廣義遺產的範園，然原則上不受私法的拘束，不過遺產稅對於繼承權、財產權的干預效果，實為繼承法的「制度性保障」(institutionelle Garantie)不容忽視的重要課題。本文擬以最高行政法院94年度判字826號遺產稅判決所涉限定繼承與遺產稅限時申報協力義務之間的關係為例，評析限定繼承人為履踐民法所定公示催告期間，非因過失而逾限辦理遺產稅申報，卻遭裁處鉅額漏稅罰的妥當性。試圖藉此案例說明遺產稅的課徵不宜動輒強調自身規範的獨立、優先性，仍應遵循民事繼承法既有規則與法理，實可避免過度干預，甚或淘空憲法對於繼承制度的保障意旨；同時檢討現行司法判決過度侷限於「形式合法性」的審查，疏於從比例原則與衡平的觀點，觀照課稅決定的「實質合法性」，以致於無法充分發揮人民權利保障的功能，特別是當納稅義務人非因故意違反協力義務，卻遭裁處不合比例的鉅額罰鍰時。

A complicated legal combination exists between family and inheritance laws and estate and gift tax. Take estate tax for example, it takes almost all the legal relationship of inheritance regulated by civil code as tax prequisite. Although theoretically speaking, estate tax, the same as other taxes, is public obligation in nature and shall not be bound by civil law and agreements between private parties. However, we should not ignore the effect de facto that estate taxation may produce against the inheritance and property rights, especially in the perspective of “Institutional Guarantee”. This article is to comment the estate tax decision of 2005 No. 826 of Administrative Supreme Court. In this case, the plaintiff, as an heir, declared limited inheritance upon his father’s death. According to the civil code, the limited inheritance requires a six-month civil court procedure. But the tax administration disregarded such civil court procedure and fined NT$ 61 Million only for plaintiff’s non­compliance of the tax procedural obligation to file tax return within the due term.