| The two-day International Conference on Taxing Billionaires, held in Paris, concluded yesterday. The event attracted over 200 participants, including academics, legal experts, policymakers, and representatives from international organizations. The conference focused on the effective taxation of the ultra-rich, aiming to foster international collaboration and generate concrete, data-driven insights for academia, legal experts, and policymakers.
Day 1 focused on academic research. Scholars presented country-specific studies analyzing the effective tax rates of billionaires. Results (presentation slides) from France, the Netherlands, Italy, the United Kingdom, Brazil, the United States, Norway, and Switzerland show strikingly similar trends in billionaire wealth accumulation and low effective tax rates.
Day 2 turned to policy. During the first half of the day, discussions centred on France’s debate on taxing the ultra-rich. Speakers broadly agreed on the importance of effectively taxing the super-rich.
“All taxes included, the super-rich pay less tax than other groups, typically around 15-20-25% of their income in tax when the working class and the middle-class pay 35-40-50-55%, depending on the country.”
— Gabriel Zucman, Director of the EU Tax Observatory
A key point from the debate between Antoine Bozio, Director of Institut des Politiques Publiques – IPP, and Bastien Lignereux, tax law teacher, Université Paris Cité, was that there is nothing in case law that opposes taxing wealth on a broad basis. The economist and the lawyer agreed: we need to think together about new instruments because reintroducing old measures such as ISF is doomed to failure. (The debate will be available soon on our YouTube channel.)
Support for reform was also expressed by David Amiel, Ensemble Member of Parliament for Paris 13th Constituency, and Éric Coquerel, LFI-NFP Member of Parliament for Seine- Saint-Denis and Head of the Committee on Finance. While their proposed solutions differed, they shared a common message: We must ensure that the ultra-rich can no longer escape taxation by hiding behind their holding companies. (The debate will be available soon on our YouTube channel.)
The second half of the day focused on global perspectives with a high-level panel with Guilherme Mello, Secretary of Economic Policy at Brazil’s Ministry of Finance, Gabriel Zucman, Director of the EU Tax Observatory, and Susana Ruiz, Global lead on Tax Justice for Oxfam International, examining international efforts and legal frameworks to address billionaire tax avoidance. (The panel discussion will be available soon on our YouTube channel.)
The panelists highlighted a landmark development that took place last year under Brazil’s G20 presidency, when, for the first time, world leaders and finance ministers committed to “engage cooperatively to ensure that ultra-high-net-worth individuals are effectively taxed.” This agreement was informed by a blueprint commissioned by the Brazilian presidency and authored by Professor Gabriel Zucman, which proposes a 2% minimum tax on billionaire wealth. The measure expands on the existing international framework for minimum corporate taxation, applying its core principles to the world’s wealthiest individuals.
The panelists also agreed that the proposal is rapidly gaining momentum on the international stage. They pointed to the possible emergence of a ‘coalition of the willing’—a growing group of countries committed to pushing the initiative forward. Guilherme Mello, Secretary of Economic Policy at Brazil’s Ministry of Finance, expressed Brazil’s willingness to take a leading role in this effort.
“For the first time taxation of the super-rich is on the global agenda, and Brazil is proud to have brought the debate to the G20.”
— Guilherme Mello, Secretary of Economic Policy at Brazil’s Ministry of Finance
In a concrete step in this direction, the French National Assembly passed a bill in February introducing a 2% minimum tax on French taxpayers with net wealth exceeding €100 million. The bill is now awaiting Senate approval, with discussions scheduled for June 12. Meanwhile, broader debates are unfolding across Europe and beyond, signaling a potential shift toward greater tax fairness and stronger global cooperation.
The day concluded with a fireside chat with Thomas Piketty, EHESS, WIL and WID, who reflected on how billionaire taxation connects to the broader issue of wealth redistribution. From India to France, wealth tax proposals are gaining ground. By making wealth taxation scenarios accessible and comparable across countries, the Global Wealth Tax Simulator will empower researchers, policymakers, and citizens alike to engage in the debate. (The fireside chat will be available soon on our YouTube channel.)
The conference was organized by the PSE Stone Center in collaboration with the EU Tax Observatory, the World Inequality Lab, the Institut des Politiques Publiques, and École Normale Supérieure. |
