I. Real estate: the last blind spot of international tax transparency
Over the past fifteen years, international tax transparency has undergone a profound transformation. The end of banking secrecy, the generalisation of exchange of information on request, and above all the implementation of the OECD Common Reporting Standard (CRS), have given tax authorities unprecedented visibility over financial assets held abroad by their residents.
More recently, this movement has been extended to crypto-assets and digital platforms. By contrast, a major component of the wealth of internationally mobile individuals and families has long remained outside this transparency dynamic: real estate.
The OECD notes that cross-border ownership of real estate has increased significantly in recent years, while still being imperfectly captured by the tax authorities of taxpayers’ States of residence. This relative opacity makes it more difficult to verify rental income, capital gains, and, upstream, the origin of the funds used to acquire real estate assets.
It is against this background that the OECD published, in October 2025, its report to G20 Finance Ministers and Central Bank Governors.
II. The October 2025 OECD report: what is it really about?
The October 2025 report does not introduce a new tax, nor does it impose new direct reporting obligations on taxpayers. Nor does it amend the substantive tax rules applicable to real estate income or capital gains.
Its purpose lies elsewhere. It establishes a voluntary framework for the automatic exchange of information between tax authorities, based exclusively on information already available in domestic administrative databases.
“Information already available” refers to data that:
- is held in electronic form;
- is searchable and sortable;
- is held either by the tax administration itself or by other authorities to which it has direct access (land registries, beneficial ownership registers, etc.).
The approach is deliberately pragmatic. Rather than immediately imposing new reporting obligations on intermediaries (notaries, real estate agents, financial institutions), the OECD proposes to coordinate and leverage data that States already possess.
III. The AMAC RBI: the legal backbone of the framework
The operational framework is built around a central instrument: the Multilateral Competent Authority Agreement on the Exchange of Information on Real Estate Assets Already Available (AMAC RBI).
This agreement is directly based on the Multilateral Convention on Mutual Administrative Assistance in Tax Matters, which authorises the automatic exchange of information that is foreseeably relevant for the administration or enforcement of domestic tax laws.
From a legal standpoint, the AMAC RBI:
- is signed by the competent authorities of participating States;
- operates bilaterally within a multilateral framework;
- leaves States considerable discretion as to the scope of their participation;
- is subject to strict confidentiality and data protection safeguards.
It is therefore a tool for administrative cooperation, not tax harmonisation.
IV. A modular architecture inspired by the CRS
One of the key features of the framework is its modular architecture, designed to accommodate the diversity of domestic tax systems.
The first module focuses on asset visibility. It provides for:
- a one-off initial exchange of information on real estate assets already held abroad;
- followed by annual automatic exchanges on subsequent acquisitions.
The second module focuses on income flows. It provides for:
- annual exchanges of information on disposals of real estate assets;
- and on regular income derived from such assets.
Each State may choose to participate in one or both modules, or not to participate at all, in particular where its tax system or the principle of foreseeable relevance does not justify receiving such information.
As under the OECD Common Reporting Standard (CRS), information is exchanged:
- with the State of tax residence of the owner in the case of direct ownership;
- with the State of tax residence of the beneficial owner where the property is held through an entity (company, trust, foundation).
V. What information will actually be exchanged?
This is undoubtedly the most significant aspect for practitioners and their clients.
The AMAC RBI defines a “minimum data set”, supplemented by optional elements, detailed in the annex to the agreement.
The information concerned includes in particular:
- identification details of individuals (name, tax residence, address, tax identification number, date of birth);
- identification details of entities (name, type, tax residence, tax identification number, business registration number);
- identification of the beneficial owner;
- characteristics of the real estate asset (address, unique identifier, type of property, value, ownership rights, ownership share);
- acquisition data (price, date, method of acquisition);
- disposal data (price, capital gain, tax paid);
- regular real estate income (amount, nature, year, tax paid).
The exchanges are carried out using a standardised XML schema, according to a precise annual timetable, generally by 31 January or 30 June of the year following the year to which the information relates.
VI. A first reading: real estate enters the era of automatic transparency
Beyond the technical framework established by the OECD, the automatic exchange of information on real estate assets forms part of an issue well known to practitioners: the international mobility of taxpayers.
These mechanisms primarily affect a specific category of individuals, commonly referred to as “mobile” taxpayers, namely persons who, for professional, social or family reasons, are likely to transfer their tax residence at least once during their lifetime.
It is precisely in the context of a transfer of tax residence that the tax and reporting obligations of the host State may extend to real estate assets located in the State of origin.
By way of illustration, a taxpayer who transfers his or her tax residence to France may ultimately become subject to French real estate wealth tax (impôt sur la fortune immobilière – IFI) on his or her worldwide real estate assets. French law does, however, provide for a favourable transitional regime for new residents, under which real estate assets located outside France are exempt for the first five years following the year of arrival in France (Article 964, 2° of the French Tax Code). This so-called “protection period” is, by its very nature, temporary and calls for careful anticipation.
Similarly, French tax residence entails the obligation to declare all foreign-source rental income and gains. While tax treaties may allocate taxing rights between States, they also enable the French tax authorities, where they identify, for instance in the course of a tax audit, foreign-source income that has not been reported, to request from the other State any information at its disposal concerning the taxpayer’s tax and asset situation.
These issues are not limited to income taxation. They also extend to long-term wealth taxation, and in particular to inheritances involving real estate assets located abroad. The failure to declare real estate assets transferred by way of inheritance represents a significant risk, especially where the property is located in a State that is not bound to France by a tax treaty covering inheritance taxes. In such circumstances, access to foreign real estate information becomes a key lever for tax authorities, both to identify the existence of the assets and to assess their value and the conditions under which they are transferred.
The new OECD framework does not in any way call into question this existing treaty-based architecture; on the contrary, it builds directly upon it. Whereas tax treaties primarily organise targeted exchanges of information initiated at the request of a tax authority, the Multilateral Competent Authority Agreement on the Exchange of Information on Real Estate Assets Already Available aims to increase the intensity, scope and systematisation of such exchanges, by introducing an automatic, regular and large-scale exchange of information already available.
In other words, the novelty does not lie in the ability of the tax authorities to access foreign real estate information, which already exists, but in the shift from a logic of ad hoc exchange to one of structured, automated and massive exchange, comparable to that implemented for financial assets over the past several years.
