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Our professionals


Ariane Guimarães

Ariane Guimarães
55 61 3218 6035 ariane.guimaraes@mattosfilho.com.br Brasília


Ariane focuses her practice on tax litigation, particularly on legal strategies in Brazil’s superior courts. She assists clients with managing the impacts of court decisions on business and represents interests before the executive (Ministry of Economy) and legislative branches (National Treasury Policy Council and National Congress), coordinating the firm’s Government Relations practice. A vice-chairman of the Brazilian Bar Association – Federal District Chapter’s Superior Courts Commission (2022-2024), Ariane is also vice-president of the Legislation Committee of the American Chamber of Commerce (Amcham).


Ariane is a professor of Tax Law at the Centro Universitário de Brasília (UniCEUB), the founder and coordinator of the Group of Studies and Research in Tax Law (GEPAT), as well as the founder of ‘Elas Pedem Vista’, a group that discusses current issues related to women in power. She is also a member of the firm’s Pro Bono Committee.


Bachelor of Laws – Centro Universitário de Brasília (UniCEUB)

Master in Tax Law – Centro Universitário de Brasília (UniCEUB)

Doctorate in Tax Law – Centro Universitário de Brasília (UniCEUB)

Visiting researcher – Georgetown University, USA


Análise Advocacia – Tax (2018-2019); Brasília (2017-2019); Financial Markets (2017)

Chambers Brazil (formerly Latin America) – Tax: Centre West (2017–2020)

The Legal 500 – City Focus Brasilia – Tax (2022)

Leaders League – Leading Brasília (2022)

Único. The Mattos Filho news portal

Authored publications

Mattos Filho in the media

With Ariane Guimarães

Brazilian Supreme Court’s new ruling regarding the ISS on franchise agreements

During virtual court sessions held between May 22 and 28, 2020, the Brazilian Supreme Court (“STF”) decided that the levy of the Brazilian Tax on Services (“ISS”) on franchise agreements is constitutional. The case under analysis (Extraordinary Appeal No. 603,136) discussed the collection of ISS on a franchise agreement of a food supply franchise. 

In summary, the discussion on the levy of ISS focuses on the fact that Brazilian franchise laws, both the old (Law No. 8,955/1994) and the new (Law No. 13,966/2019), establish that the franchise system is one in which a franchisor authorizes a franchisee to use its trademark and other intellectual property rights, associated with the right to produce or provide products or services, as well as the right to use methods and systems for implementation and management of its business. In other words, the franchise agreement has a hybrid legal nature involving the “legal obligations ‘to give/deliver’ something and ‘to do’ something”. 

Historically, the STF had recognized “the provision of services” as the element for the levy of ISS referred to as a “legal obligation ‘to do’ something”, as verified in several rulings and in the STF’s Binding Precedent 31,  which rules that the levy of ISS on lease agreement transactions[1] is unconstitutional since it refers to a “legal obligation ‘to give/deliver’ something and not ‘to do’ something”.

However, with the present ruling, the STF changed its historical understanding and determined with the effect of general application that “The levy of ISS on franchise agreements (items 10.04 and 17.08 of the service list attached to Supplementary Law No. 116/2003) is constitutional.”

It should be noted that STF Justice Gilmar Mendes, in his winning vote, clarified that the Binding Precedent 31 shall not be applied in transactions of a hybrid legal nature.

Given the impact of this decision, the representatives of industry have informed that a Motion for Clarification will be filed requesting the modulation of the effects of the decision, in order for it to be applied prospectively only.

Our team will continue to follow the updates on the case and is at your disposal for any clarification. For more information on this subject, please contact our Intellectual Property and Tax practices.

[1] As recalled in the vote of Justice Celso de Mello and Justice Marco Aurelio, who diverged from the majority. 

Areas of expertise

Mattos Filho promotes eight and passes 100-partner mark

Mattos Filho, has become the largest Latin American firm by partner count after promoting eight more of its lawyers to the partnership.

The firm promoted across its Brasília, São Paulo and Rio de Janeiro offices, boosting its M&A, infrastructure, investment fund, tax and real estate departments. Click here and learn more.

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