According to the new Roman law:
"No Jew shall marry a Christian woman, nor shall any Christian man marry a Jewess.
For if any person should commit an act of this kind, the crime of this misdeed shall be considered the equivalent of adultery and freedom to bring accusation shall be granted to the public." [CTh 3.7.2]
So, first intermarriage is forbidden. Second, the crime of intermarriage is treated as equivalent to adultery. Third, anyone at all in the public, not just relatives, can bring an accusation against people who have committed this crime.
Previous prohibitions against intermarriage focused primarily on Christian women being seduced by Jewish men, and that's the concern which is carried through most anti-Semitic legislation in history, but this decree gives equal weight to Christian men marrying Jewish women.