A reform of staff benefits is not unlawful merely because it is financially less favourable. In the same sense, a staff benefit is not an acquired right merely because it existed when the official joined the organisation. Nor does the fact that contributions were previously paid necessarily change that analysis.
For an acquired right to arise, the amended term must form part of the essential structure of the employment relationship. It must be a fundamental term that can reasonably be said to have induced the official to accept appointment, or to remain in service.
The invalidity lump sum did not meet that threshold.
This confirms the Tribunal’s restrictive approach to acquired rights. But it should not be read as a carte blanche.
Staff regulations are not frozen in time. International organizations may reform benefit schemes. But such reforms remain subject to legal limits, including procedural legality, non-retroactivity, equal treatment and, where relevant, the duty of care.
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Bert Theeuwes is a Belgian lawyer and partner at Monard Law, where he heads the international civil service law practice. He is an expert with more than 25 years of experience advising international organizations worldwide on staff regulations, internal governance, employment-related disputes and best-practice compliance. His work focuses on helping international organizations align their internal rules with administrative-tribunal case law, modern HR standards and the practical realities of international public administration.
