## Facts

- Stanislas Aquarone was a retired former Registrar of the International Court of Justice (ICJ) who settled in France after leaving office.
- During the tax years 1981–1986, Aquarone received retirement payments connected to his prior ICJ/UN service.
- Aquarone did not declare these retirement payments for French income-tax purposes, asserting they were exempt from French income tax.
- French tax authorities assessed income tax on the retirement payments under French income-tax legislation.
- Aquarone challenged the assessments in the French administrative courts, arguing that (a) the ICJ Statute’s provisions on remuneration and related benefits required exemption, and (b) in any event, customary international law on privileges and immunities of international civil servants barred France from taxing the payments.
- The Cour administrative d’appel de Lyon rejected Aquarone’s claim and upheld the application of the French tax law.
- Aquarone filed a pourvoi en cassation to the Conseil d’État (Assemblée), France’s highest administrative court, seeking annulment of the Lyon judgment and relief from the tax assessments.

## Issues

1. Whether provisions of the ICJ Statute concerning the remuneration of the Court and its Registrar extend to exempt the Registrar’s retirement payments (pension) from French income tax.
2. Whether customary international law, assuming it grants tax immunity for such retirement payments, can be applied by French administrative courts to set aside or neutralize a contrary French statute imposing income tax.

## Decision

- The Conseil d’État rejected Aquarone’s appeal and left the tax assessments in force.
- The court held that the ICJ Statute did not provide a basis to exempt Aquarone’s retirement payments from French income tax.
- The court held that rules of customary international law may be applicable in French domestic law, but they do not have priority over a legislative provision; therefore, custom could not be used to defeat the French income-tax statute.

## Legal Principles

- International instruments granting fiscal privileges are interpreted according to their terms; provisions addressing remuneration in office do not automatically extend to retirement pensions absent clear text.
- French administrative courts may take account of customary international law as part of the applicable legal framework when it is established and when no statute points the other way.
- Unlike treaties (which may take priority over statutes under the French Constitution), customary international law does not permit French courts to disregard a conflicting statute.
- When a French statute clearly requires taxation, an asserted customary rule granting immunity cannot be invoked to defeat that statute in administrative litigation.

## Conclusion

In *In Re: Aquarone*, the Conseil d’État upheld France’s taxation of a retired former ICJ Registrar’s retirement payments, ruling that the ICJ Statute did not exempt the pension and that customary international law, even if it recognized such an immunity, could not override a contrary French legislative provision imposing income tax.


In Re: Aquarone, 101 Rev. Gen. Dr. Int. Pub. 838, 92 Am. J. Int’l L. 764 (1997)