"le Service des domaines" is the old name that everyone keeps using for
Direction de l'immobilier de l'État [une direction du Ministère chargé des finances, rattachée à la Direction générale des Finances publiques (DGFiP), et principalement chargée de superviser la gestion du patrimoine immobilier de l'État mis à la disposition des ministères et des établissements publics nationaux.]
So, "le Service des domaines"
a kind of "managing agency / estate agency" for all real estate
in state / public ownership, as in:
https://www.economie.gouv.fr/cessions IOW it's got N_O_T_H_I_N_G to do with any kind of "Land Registry" - just because both "le Cadastre" and "le Service des domaines" have
something to do with land/properties
doesn't automatically mean that these are interchangeable synonyms!)
Point of method: if you are translating a text about cars engines, you can't just randomly pick for your translation the name of some/any engine part -
it's got to be the right one!
Another element: these "avis" are far more than simple "opinions" - they carry far more weight than an informal "valuation" by your local estate agent.