Regulations Governing the Employment of Foreigners by Elementary and Secondary Experimental Education Schools and Institutions Article 8

A foreign employee of a school or an institution who engages in teacher training, curriculum development, or activity promotion is not permitted to teach any subject or foreign language course. The number of such foreign employees the school or institution employs shall be in accordance with the employment plan referred to in Paragraph 1 of Article 4, and the number of hours they work shall be arranged in accordance with their employment contract as stipulated in Paragraph 4 of Article 6.
中文原文 高級中等以下實驗教育學校及機構聘僱外國人辦法第8條
學校、機構聘僱從事師資養成、課程研發及活動推廣工作之外國人,不得從事學科、外國語文課程教學;其聘僱人數依第四條第一項之聘僱計畫辦理;其工作時數依第六條第四項之聘僱契約辦理。

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