Art. 771.Rules Applicable

Louisiana groups several kinds of claims under one label: an incidental demand. It covers a reconventional demand (a defendant's claim back against the plaintiff, similar to what other states call a counterclaim), a cross-claim (a claim between co-parties on the same side of the case), an intervention (a third party stepping into an existing suit to protect its own interest), and a third-party demand (a defendant bringing in someone new, often to seek indemnity or contribution). Each of these is incidental because it rides along with, and depends procedurally on, the principal demand — the original lawsuit the plaintiff filed.

Article 771 makes a short but consequential point: the rules that govern who has the capacity to sue or be sued in the principal demand, and who is the proper defendant for particular categories of parties, apply equally to incidental demands. If a third-party defendant in an incidental demand happens to be an unemancipated minor, a succession, a partnership, or any other category Articles 641 through 742 address, the same rules for identifying the proper party apply just as they would if that party had been sued in the original petition.

The article reaches further than party capacity alone. It also folds in the substitution-of-parties rules in Articles 801 through 821, so if a party to an incidental demand dies, transfers an interest, or otherwise needs to be replaced during the case, the same substitution mechanics apply there too.