The title of a novel from Qidian is about a Vietnam War soldier who was wrongly accused and later went to France to join the Foreign Legion.

It should be the novel "Honor". The protagonist is named Pao Yulin. He is not the child of a Vietnamese he met in Hong Kong. He was in a prisoner-of-war camp in Vietnam and raped the guards of the prisoner-of-war camp (I remember he should be the protagonist) He was injured in a field hospital when the Vietnamese attacked the hospital and was captured. The people who organized the prisoner of war camp escaped and seemed to have killed the sister of the female guard. All the actions against him were blocked.) The female guard later smuggled to Hong Kong.