Parol evidence rule and the CISG

The parol evidence rule forms part of the Anglo-American common law and governs what kinds of evidence is considered when determining the specific terms of a contract. Whether the rule is relevant when the contract is governed by the CISG has been decided divergently:

Parol evidence rules cannot be applied to CISG contracts:

MCC-Marble Ceramic Center, Inc. v. Ceramica Nuova D'Agostino S.p.A.
U.S. Court of Appeals (11th Circuit)
USA, 29 June 1998 – 97-4250, CISG-online 342

Held that Art. 8(3) CISG "is a clear instruction to admit and consider parol evidence regarding the negotiations to the extent they reveal the parties' subjective intent"

Mitchell Aircraft Spares, Inc. v. European Aircraft Service AB
U.S. District Court for the Northern District of Illinois
USA, 27 October 1998 – 97 C 5668, CISG-online 444

Art. 8 CISG "requires the court to consider parol evidence in as much as that evidence is probative of the subject intent of the parties. This conclusion is in accord with the great weight of persuasive authority on the issue."

Shuttle Packaging Systems, L.L.C. v. Jacob Tsonakis, INA S.A. et al.
U.S. District Court for the Western District of Michigan
USA, 17 December 2001 – 1:01-CV-691, CISG-online 773

International sales agreements under the Convention are not subject to the parol evidence rule

Parol evidence rules can be applied to CISG contracts:

Beijing Metals & Minerals Import/Export Corp. v. American Business Center, Inc.
U.S. Court of Appeals (5th Circuit)
USA, 15 June 1993 – 92-2171, CISG-online 89

The parol evidence rule (under Texas law) applies also to CISG contracts

Weihai Textile Group v. Level 8 Apparel, LLC et al.
U.S. District Court for the Southern District of New York
USA, 28 March 2014 – 11 Civ. 4405(ALC)(FM), CISG-online 2923

Bibliography on the parol evidence rule and the CISG:

Roberta Peleggi, 'Parol evidence rule e ammissibilità della prova extratestuale nei contratti scritti: qualche riflessione in chiave comparatistica', Diritto del Commercio Internazionale (Dir. com. int.) (2012), 1009–1046 [– in Italian]

Alberto L. Zuppi, 'The Parol Evidence Rule, International Electronic Documents and the United Nations Convention on Contracts for the International Sale of Goods (CISG)', in: Camilla Baasch Andersen & Ulrich G. Schroeter (eds.), Sharing International Commercial Law across National Boundaries: Festschrift for Albert H. Kritzer on the Occasion of his Eightieth Birthday, London: Wildy, Simmonds & Hill (2008), 640–654 [– in English]

Peter J. Calleo, 'The inapplicability of the parol evidence rule to the United Nations Convention on Contracts for the International Sale of Goods', 26 Hofstra Law Review (Hofstra L. Rev.) (2000), 799–833 [– in English]

Karen Halverson Cross, 'Parol Evidence Under the CISG: The "Homeward Trend" Reconsidered', 68 Ohio State Law Journal (Ohio St. L.J.) (2007), 133–160 [– in English]

Louis F. Del Duca, 'Implementation of Contract Formation Statute of Frauds, Parol Evidence, and Battle of Forms - CISG Provisions in Civil and Common Law Countries', 38 Uniform Commercial Code Law Journal (UCC L.J.) (2005), 55 [– in English]

Louis F. Del Duca, 'Implementation of Contract Formation Statute of Frauds, Parol Evidence, and Battle of Forms - CISG Provisions in Civil and Common Law Countries', 25 Journal of Law & Commerce (J.L. & Com.) (2005), 133–146 [– in English]

David H. Moore, 'The Parol Evidence Rule and the United Nations Convention on Contracts for the International Sale of Goods: Justifying Beijing Metals & Minerals Import/Export Corp. v. American Business Center', Brigham Young University Law Review (BYU L. Rev.) (1995), 1347–1376 [– in English]

Bruno Zeller, 'The parol evidence rule and the CISG - a comparative analysis', 36 Comparative and International Law Journal of Southern Africa (CILSA) (2003), 308–324 [– in English]