Cases by type of dispute

Contract disputes are the fastest (eight months on average), thanks to the expedited procedure. Authenticity disputes last nine months, including the appraisal. Provenance disputes reach fourteen months because of archival research, and restitution disputes seventeen months, because of their complexity and the participation of States.

The gaps are larger depending on whether the tribunal has one or three arbitrators and whether the parties use mediation or not.

For contracts, 52% of disputes are settled before the hearing, often by mediation (70% agreements). In authenticity, 48% of claims are upheld in whole or in part. In provenance, 44% of cases end in an amicable agreement, and in restitution 58%.

Mediation is therefore very effective in disputes where a lasting relationship or a symbolic dimension is at stake, that is, in restitution and provenance.

The share of contract disputes rose from 24% to 33%, with the spread of the standard clause. The share of authenticity remains stable, while restitution doubled (from 7% to 14%), driven by the engagement of States and museums. Provenance disputes are stabilising at around 22%.

This development encourages the tribunal to strengthen its skills in international law and intercultural mediation.

Amounts vary by family: median of €150,000 for contracts, €320,000 for authenticity, €600,000 for provenance. Restitutions often concern property of great cultural rather than financial value, which makes the measure of the amount less relevant.

Mixed cases (for example a sale whose authenticity is contested) are classified according to the main object of the claim. The tribunal may entrust them to a panel combining several chambers.