Other: disclosure (maybe not in this case, though).

It is a standard phrase in banking literature as in the following ads.

1. Mortgage Advice Service - United Kingdom. Independent Mortgage Advisers.

2. Avoncourt's mortgage advice service offers you the opportunity...

In legal context you inform your buyer about any obligation on the subject to be sold or to be transfered .
in agreements , especially sales of company shares (take overs) there are some clauses regulating represantations made by "seller" about their liabilities on the subject of transfer .
(and even there are some clauses to make the transaction null upon some misrepresantation of facts and liabilities).
perhaps in this context represantition best fit.

as a correction to prev.

of the purchaser, perhaps.

Is any further context available Mary? What intrigues me here is the use of the singular "un renseignement". Any indication as to what the piece of information being referred to is about? "Mortgage status advice" sounds highly plausible but without further details, difficult to know.

From the OXFORD DIC OF LAW and FT/Pitman Publishing Dictionary of Law (Curzon)

Official search (UK)

A search into registers of local land charges, the Land Charges Dept or the HM Land Registry to disclose any registered matter relevant to the acquisition. Registrar returns a certificate with details of encumbrances. In the case of a mortgaged property, the “charges register” (UK) details interests which are adverse to the proprietor : mortgages, restrictive covenants to easements. This search is usually carried out by the solicitor, or conveyancer

From http://www.wwlia.org/ca-re4.htm (title search - Canada)

First, he will do what is called a title search. This means he will search the records of the Land Registry Office to find out who the registered owner is and what encumbrances, if any, are registered against it. This includes all mortgages, liens, easements, and so on. He should review this with you if his search reveals anything that you did not agree to accept in the offer to purchase and make sure that you are aware of the state of title.

Why not? It's used all the time when applying for mortgages.
Or if it's really just one piece of information:

a mortgage detail

Depends on the context.