I heard something similar to that
Sylvia Stolz who was Ernst Zundel's defense attorney was arrested for presenting evidence that Ernst Zundel was telling the truth and therefore could not have been committing a crime by saying what he said about the holocaust
Supposedly the court said that it does not matter if what he said is true, denying the holocaust is a crime and by presenting evidence that he told the truth you are guilty of holocaust denial & she was imprisoned