2 It is with sorrow that We view the recently disseminated law in Peru. Under the appearance of regulating the marriage of non-Catholics, it introduced in effect, what is called a civil marriage, even though that law does not affect people of all conditions. What is more, putting aside the authority of the Church, a civil ceremony is permitted for mixed marriages whenever the Holy See, for serious reasons and for the eternal salvation of the Christian family, would consider it inappropriate to exempt anyone from the law forbidding marriage between those of different faiths.
Source: Quam Religiosa (Vatican.va)