The Convention on Mutual Tax Assistance is an agreement designed to facilitate the conclusion of bilateral agreements for the exchange of tax information between States Parties. The convention, drawn up by the OECD and the Council of Europe, was opened for the signature of members of both organisations on 25 January 1988 and came into force in 1995. The Convention facilitates international cooperation in favour of better functioning of national tax legislation, while respecting the fundamental rights of taxpayers. It provides for all possible forms of administrative cooperation between states on taxation and tax collection. This cooperation ranges from the exchange of information, including automatic exchanges, to the collection of foreign tax debts. This enhanced mutual assistance must contribute to the fight against tax evasion and will be accompanied by safeguards to protect taxpayers, individuals or businesses, and the savings of economies. Thus, a contracting party may refuse to provide information if it would involve the disclosure of trade, industrial or professional secrets or assistance related to a tax which it considers to be inconsistent with generally accepted tax principles. Moreover, the application of the convention must not restrict the rights and guarantees recognized to the person by the state`s right of support. There are strict rules regarding the secrecy of the information obtained during the application of the text. Since 2009, the G20 has repeatedly called on countries to sign the convention, including at the 2018 G20 summit in Buenos Aires, where the communiqué said: “All countries should sign and ratify the multilateral convention on mutual tax assistance.” The text of the amended agreement is available in English, French, German (unofficial translation), Spanish (unofficial translation) and Portuguese (unofficial translation). . In addition, any State wishing to accede to the Convention may adapt the extension of its obligations because of a detailed system of reservations expressly provided for by the text; it may limit its participation in certain types of administrative assistance or assistance related to certain taxes.

. This treaty allows the contracting parties, Council of Europe member states and OECD Member States to develop, on a common basis and in respect of the fundamental rights of taxpayers, comprehensive administrative cooperation covering all compulsory taxes, with the exception of customs duties. The types of assistance are multiple and include the exchange of information between the parties, simultaneous tax controls and participation in tax controls in other countries, the collection of taxes due in other contracting parties and the notification of documents issued by other contracting parties. 141 courts are currently participating in the convention, including 17 territorial extension jurisdictions. It is a wide range of countries, including all G20 countries, all BRIICS, all OECD countries, major financial centres and a growing number of developing countries. . In accordance with Article 24, paragraphs 3 and 4 of the convention, the coordinating body is responsible for monitoring the implementation and development of the convention, including: as of September 2018, only one state (the United States) is a party to the original convention, 26 states have ratified the original 1995 convention and the amendment protocol, while 65 other parties to the amended convention.