A ChatGPT summary of Les milliardaires ne paient pas d’impôt sur le revenu et nous allons y mettre fin (“Billionaires Do Not Pay Income Tax, and We Are Going to Put an End to It”) by Gabriel Zucman (2025)
It is organized into a series of thematic sections that build a single argument: modern tax systems impose substantial burdens on ordinary citizens, while billionaires often escape income taxation through legal corporate structures. Zucman argues for a new “minimum tax” on ultra-wealthy individuals.
Below is a detailed English summary of each section.
Introduction: Billionaires Do Not Pay Income Tax
Zucman opens with a reflection on his fifteen years of research into tax avoidance and global wealth. He initially focused on offshore tax havens such as Switzerland, Luxembourg, the Cayman Islands, and the British Virgin Islands. Later, he studied how multinational corporations shift profits to low-tax jurisdictions.
However, he argues that the most important tax injustice is not hidden in exotic tax havens. Instead, it occurs in plain sight within national tax systems themselves. The central problem is that many billionaires legally receive little or no taxable personal income, despite becoming dramatically wealthier every year.
As a result, even if French billionaires moved to the Cayman Islands tomorrow, French tax revenue would hardly change, because they already pay very little income tax in France.
The book's purpose is to explain why this happens and how it can be corrected.
1. Dispelling the Opacity: An International Research Project
Zucman explains that for decades it was surprisingly difficult to know how much tax billionaires actually paid.
Traditional statistics agencies measure income and taxation for ordinary citizens, but they often fail to capture the true economic income of the ultra-rich. Publications such as Forbes and Challenges estimate billionaire wealth, but they cannot determine actual tax burdens.
Beginning in the late 2010s and early 2020s, researchers gained access to administrative tax records in several countries. This allowed economists to connect wealthy individuals to the corporations they own and to calculate their real economic income.
Studies conducted in the United States, France, Brazil, the Netherlands, Italy, Sweden, and Norway revealed a striking pattern:
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Billionaires consistently pay much lower effective tax rates than the rest of society.
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This is not an isolated national problem.
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It is a structural feature of modern capitalism.
According to Zucman, these findings fundamentally changed economists' understanding of inequality and taxation.
2. The Average French Citizen Faces a 51% Tax Burden
The next section establishes a benchmark.
Using national income accounting, Zucman calculates the total income generated by French residents. He argues that national income is the most comprehensive measure because it includes:
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Wages
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Business profits
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Interest
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Dividends
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Rental income
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Retained corporate earnings
When all taxes and mandatory contributions are considered—including income taxes, payroll taxes, VAT, and corporate taxes—the average French resident effectively contributes approximately 51% of their income to public finances.
This figure is important because it provides a meaningful comparison point for evaluating the tax burden of different social groups.
The key conclusion is that France is not a low-tax society. The average citizen contributes a substantial share of their economic income to the state.
3. All Social Classes Pay High Taxes
Zucman then examines how taxes are distributed across the population.
Using official data from INSEE and other sources, he shows that:
Working-class households
Pay roughly 45% of their income in taxes and social contributions.
Their burden comes largely from:
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VAT
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Fuel taxes
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Social contributions
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Generalized social contributions (CSG)
Middle-class households
Pay approximately 50%.
They face increasing burdens from:
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Income taxes
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Property taxes
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Social contributions
Affluent households
Generally pay slightly above 50%.
They pay additional corporate taxes through their ownership of businesses and investments.
The surprising finding is that France's overall tax system is only mildly progressive. Most social groups cluster around similar effective tax rates.
There is, however, one major exception.
4. The Effective Tax Rate of Billionaires: 13%
This section contains the book's most provocative claim.
Research by French economists found that when billionaires' true economic income is measured—including profits retained inside companies they own—their effective tax burden is dramatically lower than that of ordinary citizens.
The figures suggest:
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Average French citizens pay about 51%.
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Billionaires pay approximately 25% in total taxes.
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Their actual personal income tax burden is often around 2% of their true economic income.
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When measured relative to overall wealth growth, the burden can fall even further, leading to estimates around 13%.
The primary reason is that most billionaire wealth accumulates inside holding companies.
Corporate profits may increase the owner's wealth enormously without being classified as taxable personal income.
As a result, billionaires can become richer by hundreds of millions of euros while reporting relatively little taxable income.
5. Income Tax: An Incomplete Revolution
Zucman argues that the modern income tax, introduced in the early twentieth century, was a democratic revolution.
Its purpose was simple:
People with greater ability to pay should contribute more.
Yet the system remains incomplete.
Most citizens receive income directly as:
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Salaries
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Pensions
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Professional earnings
These forms of income are immediately taxable.
Billionaires, however, receive wealth increases through corporate ownership.
Instead of paying themselves taxable income, they allow profits to accumulate inside corporations or holding companies.
Because the legal definition of income does not fully capture these gains, the wealthiest individuals often remain largely outside the reach of progressive income taxation.
According to Zucman, this loophole undermines the original purpose of income tax.
6. A Fundamental Injustice
This section turns from economics to political philosophy.
Zucman argues that billionaire under-taxation violates one of the core principles of modern democracy:
Equality before taxation.
The French Declaration of the Rights of Man and Citizen (1789) established that public burdens should be shared fairly.
Yet the evidence suggests that the richest citizens often pay lower effective tax rates than teachers, nurses, engineers, or small business owners.
The issue is not merely symbolic.
The wealth of France's richest families has grown enormously over the last three decades.
As billionaire fortunes rise faster than the economy itself, the fiscal consequences become increasingly significant.
What once seemed a marginal issue now affects public budgets, public services, and social cohesion.
7. Yes, Billionaires Really Are Under-Taxed
Zucman addresses common objections.
Objection 1:
"The richest 10% already pay most income taxes."
His response:
This statistic refers to millions of upper-middle-class and professional households, not billionaires.
Doctors, executives, and entrepreneurs often face tax rates above 50%.
The problem concerns a tiny group at the very top.
Objection 2:
"Money inside holding companies does not belong to billionaires."
Zucman rejects this claim.
He argues that billionaire-owned companies function as extensions of personal wealth.
Owners can:
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Reinvest funds
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Purchase assets
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Acquire companies
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Influence media
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Fund philanthropic projects
The wealth is economically available to them even if it is not formally distributed as taxable income.
Therefore, excluding these resources from income measurements creates a misleading picture.
8. The World: A Tax Haven for Billionaires
The phenomenon is not uniquely French.
Studies in:
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France
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Italy
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Brazil
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Sweden
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Norway
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The Netherlands
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The United States
all reveal similar patterns.
In every country examined, the effective income tax burden of billionaires is extraordinarily low.
The United States is a partial exception because reforms introduced during Franklin Roosevelt's New Deal targeted personal holding companies and limited some avoidance strategies.
Nevertheless, even in America, billionaires often pay far less than ordinary workers relative to their economic gains.
Zucman concludes that the world has effectively become a tax haven for billionaires.
9. The Minimum Tax: The Most Powerful Tool
This section presents Zucman's proposed solution.
He advocates a minimum tax on ultra-wealthy individuals.
The principle is straightforward:
No billionaire should be allowed to pay below a certain minimum effective tax rate.
His proposal, presented to the G20 in 2024, would:
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Apply to individuals with wealth above approximately $100 million.
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Impose a minimum annual tax equal to roughly 2% of wealth.
If existing taxes paid fall below this threshold, the taxpayer would pay the difference.
Zucman estimates that such a policy could generate:
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Hundreds of billions of dollars globally.
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Tens of billions of euros annually in Europe.
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Around €20 billion annually in France.
The proposal targets only a very small number of extremely wealthy households.
10. An Effective Mechanism
Zucman argues that a minimum tax succeeds where traditional anti-avoidance measures fail.
Rather than attacking individual loopholes one by one, it establishes a universal floor.
Whether wealth is hidden through:
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Holding companies
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Trusts
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Shell corporations
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Complex ownership structures
the minimum tax would still apply.
He compares it to the recent global minimum corporate tax adopted by more than 130 countries.
Just as multinational firms can no longer reduce their tax rates below a global minimum, billionaires should face a similar floor.
The key innovation is that the tax is based on wealth rather than declared income, making avoidance far more difficult.
11. Bringing Billionaires into National Solidarity
In the concluding section, Zucman addresses concerns that a minimum tax would damage investment, innovation, or economic growth.
He argues that similar objections were raised against progressive income taxation a century ago, yet the twentieth century witnessed unprecedented economic growth.
The proposed tax would not confiscate wealth.
Instead, it would merely require billionaires to contribute at least a minimum amount comparable to what ordinary citizens already contribute.
For most billionaires, whose wealth typically generates returns well above 2% annually, the tax could be paid entirely from investment income.
Zucman presents the reform as the logical completion of the democratic project that began with the invention of modern income taxation.
His final message is that billionaires should not exist outside the fiscal rules governing everyone else. A minimum tax would restore equal treatment before the law and reintegrate the ultra-rich into the social contract that underpins democratic societies.
