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CERN Taxation System
This page is for general informational purposes only. It does not constitute tax or legal advice. Always consult a qualified tax advisor for your specific situation.
CERN Internal Tax
CERN levies its own internal tax on salaries, which is deducted directly from your pay slip each month. This is not a national tax -- it is administered internally by CERN, with progressive rates similar in structure to a national income tax. The internal tax has been in force since 1 January 2005, pursuant to the Protocol on Privileges and Immunities signed by Member States in 2004 and the CERN Council decision of 15 September 2005.
The internal tax is mandatory for all CERN staff and is calculated automatically each month. No action is needed on your part -- you will see the deduction on your pay slip alongside other standard deductions.
National Income Tax Exemption
Under the Protocol on Privileges and Immunities of international organisations, CERN salaries are exempt from national income tax. This exemption applies in the host states (Switzerland and France) and in most CERN member states. However, it is important to understand that the exemption covers only your CERN salary -- other income from investments, rental property, or freelance work remains subject to normal taxation in your country of residence.
French Citizens Exception
French nationals working at CERN and living in France may be subject to French income tax on their CERN salary, which is an exception to the general exemption rule. Special provisions apply and the situation can be quite complex, so if you are a French citizen, it is essential to consult a tax advisor. This exception applies regardless of the type of contract you hold at CERN.
Swiss Residents
If you live in Switzerland, no Swiss income tax applies to your CERN salary. However, the wealth tax (impot sur la fortune) still applies at cantonal and communal level, and any non-CERN income -- from rental property, investments, or self-employment -- is subject to Swiss cantonal and communal taxes. You must file an annual Swiss tax return declaring your wealth and any non-CERN income.
French Residents
For non-French nationals living in France, no French income tax applies to your CERN salary. Nevertheless, you must still file an annual French tax return and declare your worldwide income, including your CERN salary -- which is entered as exempt income. Any non-CERN income from rental property or investments is subject to French income tax at standard rates.
Be aware that the taux effectif may apply: even though your CERN salary is exempt, it can be taken into account when calculating the tax rate applicable to your other income, potentially resulting in a higher marginal rate on that non-exempt income.
Outside Income
Income from investments, rental property, freelance work, or other sources is taxable in your country of residence, regardless of your CERN status. You must report all non-CERN income in your annual tax return. Double taxation treaties between countries may affect how this income is taxed, so it is advisable to consult a qualified tax advisor if you have income from multiple sources or countries.
Spain-Specific Considerations
CERN employees who maintain their tax residence in Spain have specific obligations. The CERN salary is exempt from IRPF, but it must be declared.
Additionally, Modelo 720 obligations for declaring foreign assets apply when the established thresholds are exceeded.
Practical Tips
Keep all your CERN pay slips, as you will need them for your tax returns. Always declare your CERN salary in your tax return, even if it is exempt -- failing to declare it can cause problems with tax authorities. If you have a complex situation, such as dual residence or multiple income sources, consulting a qualified tax advisor is strongly recommended.
Remember that tax treaties between countries can significantly affect your situation. Your obligations may vary depending on your nationality and country of residence, so it pays to understand the specific rules that apply to you.