Han Duck-Soo is accused, among other things, of perjury and having falsified and destroyed official documents.
Yoon Suk-Yeol shocked South Korea when he declared martial law in December last year to protect the country from "communist forces". He was removed from office in early April when the Constitutional Court in an impeachment proceeding decided that the declaration did not meet the legal requirements for a national crisis.
Yoon is accused of several crimes in connection with the incident. He has previously denied the allegations and has insisted that he had the authority to introduce martial law.
With the indictment against Kim, the former presidential couple is the first in South Korea to be put on trial at the same time.
