Sefer Ha’mitzvos Ha’Katzar (The concise book of mitzvos) By the Chofetz Chaim

This book lists the Torah mitzvos that can be observed today

Second Section – the Negative Commandments

39. It is a negative commandment “Do not give false testimony.”

As it states in Shemos (Exodus) 20:13, “do not act as a false witness against your friend.” If a person gives testimony given to him from other people, even if the other people are trustworthy, he has transgressed this negative commandment. If a person hires a false witness or supresses his testimony, he is not held liable by courts run by people in this world, but is held liable by Heavenly courts.

This applies in all places and at all times, for anyone that is fit to be a witness.