Art. 645 Pleading nonjoinder of a party

If someone who should be part of a lawsuit was left out, that problem needs to be addressed before the case moves forward. A person or party involved in the case can raise this issue by filing what's called a peremptory exception, which is a formal way of telling the court "someone important is missing from this case."

The court itself can also catch this problem, even if nobody points it out. This means a trial court or an appeals court can notice on its own that a necessary party is missing and bring it up, without waiting for one of the parties to say something.

This rule matters because some cases can't be fairly decided unless all the right people or parties are included. If someone who should be there is missing, the case might not be able to move forward properly until that's fixed.