On 17 January 2023, Ambassador Sušnik handed over the copies of the Letters of Credence to Ambassador Olivier Baldauff, Head of Protocol at the Ministry of Foreign and European Affairs of the Grand Duchy of Luxembourg, and the following day she presented the Letters of Credence to Grand Duke Henri. She was accompanied by the First Counsellor of the Embassy, Mateja Blaj.

On the evening of 18 January 2023, Ambassador Barbara Sušnik hosted a reception in the Foyer européen, managed by the Representation of the European Commission in Luxembourg, which brought together resident Ambassadors of EU Member States, representatives of the Ministry of Foreign and European Affairs and the Slovenian community, most of them employed by the European institutions.