法令翻訳 http://www.japaneselawtranslat...ky=&page=1

(給与が非課税とされる外国政府職員等の要件の細目)
第三条  令第二十四条第一号（給与が非課税とされる外国政府職員等の要件）に規定する財務省令で定める者は、日本国との平和条約に基づき日本の国籍を離脱した者等の出入国管理に関する特例法（平成三年法律第七十一号）に定める特別永住者とする。

Details of Requirements for Foreign Government Officials, etc. Whose Salaries Are Deemed to Be Exempt from Taxation
Article 3  The person specified by Ministry of Finance Order as prescribed in Article 24, item (i) (Requirements for Foreign Government Officials, etc. Whose Salaries Are Deemed to Be Exempt from Taxation) of the Order is to be a special permanent resident specified by the Special Act on the Immigration Control of, Inter Alia, Those Who Have Lost Japanese Nationality Pursuant to the Treaty of Peace with Japan (Act No. 71 of 1991).