1. (No) mandatory character of Article 4, sentence 2(b) of the CISG

524

First of all, it might appear questionable whether parties can even deviate from Article 4 of the CISG or whether this provision should be considered mandatory. Bonell opines that Article 4 is indeed not optional and cannot be derogated from or excluded by parties’ agreements.1090 If this were accurate, the parties’ freedom to regulate the transfer of property under national law under the CISG would already be ruled out. Yet, Article 6 explicitly excludes Article 12 from the parties’ freedom to modify the CISG. It can be inferred from this explicit exclusion that no deviation from other provisions of the CISG is off limits. Magnus and Ferrari argue that considering the provision to be mandatory is not necessary since a parties’ exclusion of Article 4 of the 234 CISG would not have any practical effect.1091 This is because the CISG does not provide for respective rules on validity and, thus, questions of validity would nevertheless have to be answered by applying unharmonized national law.1092 This argument can be extended to the transfer of property: While some rules of the CISG are linked to the property in the goods, they are in no way meant to provide for the point in time or requirements of the transfer of property. Thus, even if Article 4, sentence 2(b) of the CISG were excluded by party agreement, the CISG would not regulate the effect the contract has on the transfer of property under national law. Specifically rules on the delivery of the goods under Articles 31–33 should not be misunderstood to indicate that the CISG contains a preference for a transfer of property concept requiring the handing over of the goods.1093

2. Regulating the transfer of property under Article 6 of the CISG

525

That the parties may deviate from Article 4, sentence 2(b) of the CISG does not necessarily mean that the parties can effectively provide their own rules on the transfer of property or simply agree on the point in time when the property should pass under the CISG. Aboukdir has undertaken an extensive analysis of the latter question and concludes that the parties can agree on the relevant point in time and the requirements of the transfer of property due to the party autonomy provided under Article 6 of the CISG.1094 He elaborates that the CISG does not provide “default rules regarding the issue of transfer of property”, but nothing prevents the parties from agreeing on rules of their wishing.1095 Even though Article 4, sentence 2(b) of the CISG excludes the transfer of property from the Convention, Aboukdir, nevertheless, considers the matter covered implicitly by the principle of party autonomy.1096 It is not entirely clear whether his argument is meant to encompass also unascertained goods, and consequently allow the parties to transfer property in such goods.1097

526

This interpretation relies on a misunderstanding of Article 6 of the CISG. The provision allows the parties to exclude the CISG or modify its rules within its scope of application. By contrast, the CISG itself does not allow the parties to extend the scope of application. If the parties choose the CISG as the applicable law and the requirements under Article 1(1) of the CISG are not fulfilled, the effect of such a choice-of-law is subject to the applicable private international law. Nothing prevents the parties from declaring that the CISG applies to questions of transfer of property or agreeing on how the transfer of property should be considered to operate. However, if the applicable private international law declares the lex rei sitae to be applicable to questions of property, the rules by the parties on the transfer of property can only be considered to have an effect as far as the lex rei sitae accepts the regulation provided for by the parties (so-called incorporation by reference in contrast to a choice of law).1098 In the same vein and for the same reasons, the sometimes proposed choice of subsidiary law for matters not governed by the CISG1099 cannot be considered to be effective under Article 6 of the CISG. If such a choice of law is effective, this can only be due to the applicable private international law.

3. Relevance of parties’ agreement outside of the CISG

527

Although the CISG does not give effect to a parties’ agreement regarding the law applicable to property or their own respective rules, such agreements may nevertheless have an impact on the transfer of property. The CISG is merely indifferent to such agreements. It affects them neither positively nor negatively. It is up to the applicable rules of private international law to assess the effect of a choice of law regarding matters of property and up to the applicable property law to evaluate whether effect is given to the parties’ agreement on when and how property is supposed to pass.