(a) The principle of the freedom of form.

(b) Both Article 11 CISG and Article 1.2 PICC use almost identical wording, but the 2016 version of the PICC no longer uses the word ‘writing’ but rather ‘a particular form’.

(c) Under French CC, sales contracts exceeding a certain value are subject to form requirements in order to be enforceable. A similar rule can be found in Section 2-201(1) UCC, even though its paragraph 3 provides for some important exceptions.

(d) The lack of writing does not render the contract invalid, it merely prevents its enforceability. However, according to Section 2-201(3), even a contract which does not live up to the form requirements is enforceable if the seller has already made substantial beginnings or commitments for the procurement of goods that are specifically manufactured for the buyer. An unwritten contract is also enforceable to the extent to which the other party admits in court that a contract of sale was made. Finally, it is enforceable, despite the lack of writing, with respect to goods of which the buyer has already taken delivery.

(a) Yes, they can derogate from Article 11 CISG and provide for specific form requirements (cf Art 6 CISG). However, the parties’ arrangement will have no effect in those cases which are governed by Article 12 CISG and in which domestic form requirements prevail over Article 11 CISG.

(b) The CISG does not require that a modification or termination of the contract be in writing, but the parties can make a different agreement.

This sentence prevents domestic procedural rules from undermining the principle of freedom from form requirements.