A contract concluded between persons who are in the same country is formally valid if it satisfies the formal requirements of the law which governs it under this Convention or of the law of the country where it is concluded.

A contract concluded between persons who are in different countries is formally valid if it satisfies the formal requirements of the law which governs it under this Convention or of the law of one of those countries.

Where a contract is concluded by an agent, the country in which the agent acts is the relevant country for the purposes of paragraphs 1 and 2.

An act intended to have legal effect relating to an existing or contemplated contract is formally valid if it satisfies the formal requirements of the law which under this Convention governs or would govern the contract or of the law of the country where the act was done.

The provisions of the preceding paragraphs shall not apply to a contract to which Article 5 applies, concluded in the circumstances described in paragraph 2 of Article 5. The formal validity of such a contract is governed by the law of the country in which the consumer has his habitual residence.

Notwithstanding paragraphs 1 to 4 of this Article, a contract the subject matter of which is a right in immovable property or a right to use immovable property shall be subject to the mandatory requirements of form of the law of the country where the property is situated if by that law those requirements are imposed irrespective of the country where the contract is concluded and irrespective of the law governing the contract.