Yes, the summons must be obeyed. This also applies to those cases in which there is an exemption from giving evidence or a right to refuse to give evidence (see below). In the event of unjustified absence, the person may be brought before the court, provided that the summons expressly threatens to do so. If it is not possible to appear, for example due to illness, it is advisable to inform the competent court as soon as possible.
Other consequences for unexcused non-appearance are not provided for in the investigation stage. The situation is different in the main hearing. Here, a fine of up to EUR 1,000.00 can be imposed on a witness who fails to appear. If the non-appearance leads to an adjournment of the main hearing, the absent witness must reimburse the costs incurred by his absence.