Rule 122
Costs of taking of evidence

(1) The taking of evidence by the European Patent Office may be made conditional upon deposit with it, by the party requesting the evidence to be taken, of an amount to be fixed by reference to an estimate of the costs. 

(2) Witnesses or experts who are summoned by and appear before the European Patent Office shall be entitled to appropriate reimbursement of expenses for travel and subsistence. An advance for these expenses may be granted to them. This shall also apply to persons who appear before the European Patent Office without being summoned by it and are heard as witnesses or experts. 

(3) Witnesses entitled to reimbursement under paragraph 2 shall also be entitled to appropriate compensation for loss of earnings, and experts to fees for their work. These payments shall be made to the witnesses and experts after they have fulfilled their duties or tasks.

(4)¹⁴⁷ The Administrative Council shall lay down the details implementing paragraphs 2 and 3. Any amounts due under these provisions shall be paid by the European Patent Office.