Hi,
If you want to teach any language "as a foreign langugage" in a school you'll need to have a bachelor degree or more.
If I'd understood well you are French native speaker, maybe you are a half of American and French. Anyway you should know that there is competition to teach English in Taiwan and Asia as well. You will face : American, English, Canadian, Australian, New Zealander, Ireland ans many people from many countries that speak fluent English.
Many Taiwanese went abroad to study, many have a very good conduct in English.
So if you want to make the difference, (on peut dire ça en anglais ?) you'll have to show that you have some degrees, qualifications and experience.
If you just plan to teach to individual as private teaching, you can do it without any problem, you just have to find by yourself which channels & networks Taiwanese use more for seeking English teacher.
Anyway you will have more information from the USA. When arrived there watch out Taiwanese representation in America.