§1. Unless other provision is legitimately made in particular places, a decree of the diocesan bishop or a judicial sentence can decide the personal separation of baptized spouses according to the norm of the following canons.
§2. Where an ecclesiastical decision has no civil effects or if a civil sentence is not contrary to divine law, the bishop of the diocese of the residence of the spouses, after having weighed the special circumstances, can grant permission to approach the civil forum.
§3. If a case concerns only the merely civil effects of marriage, the judge, after having observed the prescript of §2, is to try to defer the case to the civil forum from the start.
Source: Code of Canon Law (Vatican.va)