I have a National/Type D visa issued by Greece for purpose indicated as "public interest" in the visa sticker (I am doing a clinical observership program in a public hospital). I arrived on October 20, and will be staying until April 26, 2020.
Am I required to apply for a residence permit, even if I am staying for less than a year? The consul herself in my home country was not sure of the answer. I read somewhere that residence permits are not required for stays more than 3 months but less than 1 year. Is this true?