The new Civil Code, unlike the old Code, includes a quasi-complete provision on the invalidity of the contract based on the fundamental distinction between absolute invalidity and relative invalidity. Invalidity – either absolute or relative – can be both complete and partial. Regardless of its form or the way it is established or in which it operates, partial invalidity may appear either as an explicit invalidity, therefore, in the form of clauses declared null or voidable or, more recently, either in the form of clauses deemed unwritten, or as tacit invalidity (obviously partial). In terms of terminology, the phrase or formula “clauses deemed unwritten” is an easy, therefore practical way to designate certain ancillary unlawful clauses which are automatically void.
Ratione temporis, partial invalidity, regardless of its form, is and shall remain subject to the law in force at the date of conclusion of the contract and not to the law in force at the date the invalidity was determined or that when the contract was cancelled and neither subject to the law in force at the date the parties are reinstated to the previous status.
