Negative Commandment #139
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
139. It is a negative commandment for a Cohain "do not marry a disqualified woman"
As it states in Vayikra (Leviticus) 21:7, "a woman that is disqualified do not take." A disqualified woman is one who is born from a woman who is forbidden to a Cohain or a woman forbidden to a Cohain that had relations with a Cohain or was married to one.
This applies in all places and at all times.