Observe · Regulate · Protect — since 2007. 19th OIMAP General Assembly: Singapore, 10–12 June 2026. Programme
Arbitration

Arbitration hearings

Preparation, conduct and organisation of TAO hearings, on site or remotely: witnesses, experts, interpreters and confidentiality.

Updated : October 28, 2026· 3 min read

The moment of the debates

Coronation of the Virgin, Christoffel Jegher (1632–36)
Coronation of the Virgin, Christoffel Jegher (1632–36)

The hearing is the moment when the parties speak before the arbitrators. It generally lasts only one to three days, but it concentrates most of the exchanges: oral arguments, examination of witnesses and experts, questions from the tribunal.

The TAO holds its hearings in Paris, Geneva, Singapore and Dubai, as well as by videoconference. Nearly half the hearings are now held remotely, which reduces costs and speeds up the timetable.

This page explains the preparation, the conduct and the practical rules.

  • Hearing
  • Debates
  • Witness

Arbitration hearings in figures

1 to 3Hearing days, generally
4Hearing venues
48%Remote hearings
6Interpretation languages

Source: Registry of the OIMAP Arbitral Tribunal.

Breakdown

Paris41%
By videoconference48%
Geneva5%
Singapore and Dubai6%

Hearing venues in 2024.

Preparing the hearing

Four weeks before the hearing, the parties confirm the list of witnesses and experts, submit their pleading documents and test the equipment. A preparatory meeting sets speaking time, the order of address and the arrangements for examination.

Interpreters are booked through the Registry. Documents to be projected are sent in advance to the tribunal and the opposing party. New documents are admitted only with the tribunal's authorisation.

Dr. James Stuart; Mary Campbell Stuart, Gilbert Stuart (c. 1815)
Dr. James Stuart; Mary Campbell Stuart, Gilbert Stuart (c. 1815)
Seal Color Box (1662–1722)
Seal Color Box (1662–1722)
The Antechamber of the Palace of Justice, Paris, Charles Meryon (1855)
The Antechamber of the Palace of Justice, Paris, Charles Meryon (1855)

The conduct of the hearing

The hearing begins with a statement by the claimant, then by the respondent. Next come the hearing of fact witnesses, that of experts and questions from the arbitrators. The parties conclude with a closing argument. A transcript is made by a stenographer or a recording system.

The president directs the debates, ensures that speaking time is respected and may interrupt to clarify a point. Witnesses take an oath or undertake to tell the truth.

Remote hearings and confidentiality

Videoconferencing uses a secure platform, with a waiting room, encryption and access limited to registered persons. Recording is allowed only with the agreement of all parties. Participants must be in an isolated room and confirm that they are not being assisted without others' knowledge.

Hearings are held in camera. Only persons registered on the file may attend. Brief minutes are drawn up and signed by the president.

After the hearing

The arbitrators may request supplementary written observations within a short time. Once the debates are closed, they deliberate in private, generally by videoconference, then draft the award. A draft is discussed among the three arbitrators before signature.

The parties receive the award through the Desk. The Registry invites them to fill in a satisfaction questionnaire, the results of which feed into the quality committee.

Practical organisation

Two formats
ElementIn personRemote
RoomTribunal premisesSecure platform
DocumentsPaper copiesScreen sharing
InterpretationBoothsDedicated channel
TranscriptStenographerApproved recording

Milestones

  1. Confirmation

    Witnesses and experts.

  2. Documents

    Filing of supporting materials.

  3. Technical test

    For remote hearings.

  4. Hearing

    Debates.

  5. Transcript

    Proofreading.

Witnesses and experts

The Dance at the Court of Herod, Israhel van Meckenem (c. 1500)
The Dance at the Court of Herod, Israhel van Meckenem (c. 1500)
Sketches in Belgium and Germany, Volume I: Hall of Justice of the Magistrates du Franc, Bruges, Louis Haghe (1840)
Sketches in Belgium and Germany, Volume I: Hall of Justice of the Magistrates du Franc, Bruges, Louis Haghe (1840)
The Triumph of Mordecai, Lucas van Leyden (1515)
The Triumph of Mordecai, Lucas van Leyden (1515)

On site or remote

The Judgment of Solomon and Esther before Ahasuerus (pair), Dirk Vellert (c. 1530)

On site

Tribunal premises
  • Direct contact
  • Tangible documents
  • Travel costs

For major stakes.

Portrait of John VIII Palaoelogus, Emperor of Constantinople, 1424-1428 (reverse), Pisanello (c. 1438–1439)

Remote

Videoconference
  • Economy and speed
  • Dispersed participants
  • Depends on technology

Increasingly chosen option.

Preparing to plead

  1. Plan

    Fix the order of addresses.

  2. Test

    Check the technology.

  3. Coordinate

    Gather witnesses and experts.

  4. Plead

    Keep to time.

  5. Proofread

    Validate the transcript.

Before the hearing

A witness

The Victory Banquet: from Battle Scenes of the Quelling of Rebellions in the Western Regions, with Imperial Poems (c. 1765–74; poem dated 1760)
« I was afraid of an intimidating courtroom. The exchange was serious but courteous, and everyone was able to speak. »
Rachid Mansouri, restorer-expert

Vocabulary of the hearing

Oral argument
Oral presentation of arguments.
In camera
Non-public hearing.
Transcript
Complete record of proceedings.
Fact witness
Person with knowledge of the facts.

Frequently asked questions

Must I be present?

Yes, or represented.

Can it be recorded?

With the agreement of all parties.

How many interpreters?

Depending on the languages.

Where can I see the costs?

See Fees.

Useful documents

Contacts

A Palace with an Arched Bridge (A Roman Villa), Hubert Robert (1760)
A Palace with an Arched Bridge (A Roman Villa), Hubert Robert (1760)
Registry of the Arbitral Tribunal (TAO)Paris — Head Office+33 1 00 00 04 00greffe.tao@oimap.exampleMonday to Friday, 9 a.m. – 5 p.m.

Consult the case law

Carnet (1863–1865)

Anonymised decisions.

Case law
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