The legal terms “Necessary Joinder of Parties” (Nužno suparničarstvo) in Serbia and “Unified Joinder of Parties” (Einheitliche Streitpartei) in Austria have essentially the same meaning in both legal systems and refer to situations in which all participants in a substantive legal relationship must sue or be sued together in the same lawsuit for the lawsuit to be successful.

If a unified joinder of parties has been established in Austria is not based on the ZPO (Code of Civil Procedure), but on substantive law, since procedural law does not impose a general obligation to pursue lawsuits simultaneously by or against all holders of a right.¹ Procedural law contains no general duty to include in the proceedings all persons who may potentially be affected by a certain legal relationship.² Therefore, substantive law must be examined to determine whether a unified joinder of parties exists, avoiding any generalizations. According to the Austrian Supreme Court (OGH), a unified joinder of parties exists when the common factual basis necessarily leads to a single decision.³

This can be illustrated by the example of joint tenants: Whether joint tenants form a unified joinder of parties cannot be generally answered. The decisive factor is the issue in the specific proceeding — the specific claim (the subject matter).⁴ What matters is whether the proceeding concerns the fulfillment of an obligation, the modification of a right, or the determination of a right. If the proceeding concerns the fulfillment of an obligation, the joint tenants do not form a unified joinder of parties.⁵ For example, if several persons jointly enter into a tenancy contract, they form, according to the Austrian Supreme Court, a community of joint tenants within the meaning of Article 825 of the ABGB (Civil Code). The Austrian Supreme Court clearly emphasizes that joint tenants hold indivisible rights over the entire property; their tenancy rights cannot be divided into individual rooms or ideal shares.⁶ However, this substantive law indivisibility does not mean that the joint tenants form a unified joinder of parties. On the contrary, each joint tenant has independent active and passive procedural legitimacy for certain claims and obligations, such as maintenance actions or claims against third parties. Since substantive law already precisely defines who may assert which claims, the ZPO does not require all joint tenants to participate in the same proceedings. From this, it may be concluded that a community of joint tenants exists, but not a unified joinder of parties.

Conversely, if a constitutive or declaratory proceeding is initiated, the participation of all joint tenants in the proceeding is necessary, and they form a unified joinder of parties.⁷ This can be illustrated by the example of terminating a joint tenancy. The Austrian Supreme Court has held that a joint tenancy relationship can be terminated only to all joint tenants. Constitutive rights are indivisible; a partial termination that would produce effects only against one joint tenant is not permitted.⁸ Therefore, a notice of termination cannot be directed at only one joint tenant but must include all of them. Judicial termination is, on the one hand, a substantive constitutive act, and on the other hand, a procedural act initiating proceedings. If the joint tenants are the ones initiating judicial termination, then all of them must participate in the proceedings (Article 560 ZPO in conjunction with Article 828 ABGB). From a procedural standpoint, the existence of a unified joinder of parties according to Article 14 of the ZPO entails that all joined parties must act jointly as plaintiffs (or be sued jointly as defendants)⁹, that the judgment must have identical effects for all joined parties, and that the procedural acts of one party extend their effects to the others (the principle of procedural favorability).

The legal position, however, looks different in Serbia: Unlike Austria, where the necessary joinder of parties is not legally defined but derived from court decisions and legal doctrine, the Serbian legislator has chosen a different path and expressly defined necessary joinder in Article 211 of the ZPP (Code of Civil Procedure).¹⁰ The Serbian legislator did not leave the definition of this concept to court decisions and legal doctrine, but has defined it directly.

According to Article 211(1) ZPP:
“Necessary joinder of parties exists when, by law or by the nature of the legal relationship, all persons who are participants in a substantive legal relationship must be included in the lawsuit.”¹¹

From this definition, it follows that in Serbia, necessary joinder exists in two situations.

In the first case, under Article 211(1) ZPP, necessary joinder occurs when it is prescribed by law.¹² For example, Article 256 of the Family Law prescribes that the parties form a necessary and uniform joinder in proceedings for contesting maternity, establishing or contesting paternity, as well as the annulment of the acknowledgment of paternity.¹³ Where necessary joinder is prescribed by law (as in cases concerning maternity or paternity), the court shall reject the lawsuit if it does not include all persons who must participate.¹⁴ While in Serbia, necessary joinder may be prescribed by law, this is not the case in Austria, where it derives from substantive law.

The second case, under Article 211(1) ZPP, occurs when necessary joinder results from the nature of the legal relationship itself.¹⁵ It typically occurs in situations involving indivisible subjective rights, indivisible civil-law relationships, or indivisible legal interests.¹⁶ When necessary joinder in Serbia occurs from the nature of the legal relationship, Serbian legal literature provides the same examples as Austrian law — such as co-owners or holders of easements on jointly owned immovable property.

A common feature of both legal systems is that a lawsuit may be filed only if all necessary joinder of parties (unified joinder of parties) are included. If this is not the case, there is a lack of legitimation, and the court in both countries is obliged to dismiss the claim. In Serbia, however, this does not apply to the first situation under Article 211(1) ZPP, where necessary joinder is prescribed by law, since in that case the lawsuit is rejected.¹⁷ Although both in Austria and in Serbia, the result is the dismissal of the claim, the manner of regulation differs. Unlike Serbia, where the dismissal of the claim in the absence of necessary joinder is expressly provided by Article 211(2) ZPP, Austria has no equivalent article, but it can be inferred from legal doctrine and court decisions in conjunction with Article 14 ZPO.

Article 211(3) ZPP provides: “The court shall consider necessary joinder ex officio (on its own motion).”¹⁸ No equivalent provision exists in Austria. It can be summarised that the greatest difference between Austrian and Serbian law regarding necessary joinder of parties (unified joinder of parties) lies in the fact that, in Serbia, this institution is expressly regulated by Article 211 of the Code of Civil Procedure, whereas in Austria, it is derived from substantive law.

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1. B. Schneider, “§ 14 ZPO”, in: ,,Kommentar zu den Zivilprozessgesetzen ” (ed. Andreas Konecny), 2015, 398. ↩︎
2. S. Perner, ,,Die notwendige Streitgenossenschaft an der Schnittstelle von Zivil- und Prozessrecht”, RdW 2/2010, 77–81. ↩︎
3. OGH 21.06.1977, 5 Ob 620/77; OGH 26.9.2018, 1 Ob 160/18p. ↩︎
4. S. Perner, ,,Die notwendige Streitgenossenschaft an der Schnittstelle von Zivil- und Prozessrecht”, RdW 2/2010, 77–81. ↩︎
5. S. Perner, ,,Die notwendige Streitgenossenschaft an der Schnittstelle von Zivil- und Prozessrecht”, RdW 2/2010, 77–81. ↩︎
6. OGH 16.01.1990, 5 Ob 511/9. ↩︎
7. S. Perner, ,,Die notwendige Streitgenossenschaft an der Schnittstelle von Zivil- und Prozessrecht”, RdW 2/2010, 77–81. ↩︎
8. OGH 27.06.1984, 1 Ob 616/84. ↩︎
9. OGH 30.7.2019, 10 Ob 26/19z. ↩︎
10. Zakon o parničnom postupku – ZPP, (“Sl. glasnik RS”, br. 72/2011, 49/2013 – odluka US, 74/2013 – odluka US, 55/2014, 87/2018, 18/2020 i 10/2023),čl. 211, st. 1. ↩︎
11. Zakon o parničnom postupku – ZPP, čl. 211, st. 1. ↩︎
12. Zakon o parničnom postupku – ZPP, čl. 211, st. 1. ↩︎
13. Porodični zakon – PZ, (“Sl. glasnik RS”, br. 18/2005, 72/2011), čl. 256. ↩︎
14. Porodični zakon – PZ , čl. 256, st. 7. ↩︎
15. Zakon o parničnom postupku – ZPP, čl. 211, st. 1. ↩︎
16. G. Stanković, Komentar Zakona o parničnom postupku, 2015, 749. ↩︎
17. Zakon o parničnom postupku – ZPP, čl. 256, st. 7. ↩︎
18. Zakon o parničnom postupku – ZPP, čl. 211, st. 3. ↩︎

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