Learn French: Je vous envoie ci-inclus les annexes à la déclaration. - I am sending you the enclosed appendices to the declaration.

This is the core rule for administrative terms like ci-inclus and ci-joint. When placed before a noun introduced by a determiner (like les in this sentence), it acts as an adverb and is invariable. If you moved it after the noun, it would become an adjective and agree: les annexes ci-incluses.

Could I put ci-inclus at the very beginning of the sentence?

Yes, you can start a sentence with it, such as: Ci-inclus, je vous envoie les annexes. When placed at the very beginning of a sentence or clause, it also acts as an adverb and remains completely invariable.

Is there a difference in meaning between ci-inclus and ci-joint?

They are often used interchangeably in formal correspondence and follow the exact same grammar rules. Technically, ci-inclus means enclosed (placed inside the same envelope or package), while ci-joint means attached (clipped to the document, or an email attachment).

Why do we use the preposition à in les annexes à la déclaration instead of de?