The Site Registration number identifies a company.
This numerical identifier made of 14 numbers is sub-divided into two parts: the first part is the Company Registration number the company (or legal unit or legal entity) to which the Site Registration number belongs; the second part is usually called the NIC (internal classification number), and is made up of a four-figure number assigned to the establishment and a control figure used to validate the Site Registration number as a whole.
This information must necessarily be entered if the Site Registration number code is setup as being mandatory for the country of the company for which the site is attached.