Under the EIO Directive : - Besides the grounds of non-recognition/execution provided under art. 11 Directive 2014/41/EU, recognition and execution might be refused where the suspected or accused person does not consent or the execution of the measure would be contrary to the fundamental principles of Luxemburg Law.
Under the EU MLA Convention of 2000: To be requested by international letters rogatory. Contents: - an indication of the authority making the request; - the object of and the reason for the request; - time and place of perpetration of the offence, and a summary of the facts; - where possible, the identity and the nationality of the person concerned; - the identification and address of the witness to be heard; - an indication of the criminal conduct under investigation, including the statutory basis and the sanctions attached thereto; - any specific procedure requested by the requesting party, in particular whether the witness is to be heard under oath or not, and whether he is to be informed about any rights in application of the procedure of the requesting State; - date and time for the video conference, taking in to account any time zone differences; - type and dialing number of the video conference equipment, with international and regional prefixes; - as the case may be, any encryption standards used for the communication. Witnesses must present themselves; unwilling witnesses may be compelled to appear by warrant. Hearings are formalised in a report. Execution of the measure in conformity with the procedure applicable in the requesting State : possible as a matter of principle; to be assessed on a case by case basis. Relevant formalities to be expressly indicated.