What are the requirements for conducting a civil aerial demonstration with hot air balloons?

In order to carry out an aerial demonstration with balloons, Royal Decree 1919/2009 applies. In accordance with Article 26 of this Royal Decree, they must submit a responsible declaration in accordance with the requirements set out in the Royal Decree, and request the publication of a NOTAM as set out in Article 18 of that Royal Decree. https://www.boe.es/diario_boe/txt.php?id=BOE-A-2010-835

With regard to take-off areas, we inform you that, according to Commission Regulation 923/2012 of 26 September 2012 laying down air regulations and common operational provisions for air navigation services and procedures; according to its sections SERA.5005, Visual flight rules and SERA.3105, minimum heights: No aircraft should conduct VFR flights over agglomerations of buildings in cities, towns or inhabited places, or over an open-air gathering at a height of less than 300 m (1 000 ft) above the highest obstacle within a radius of 600 m from the aircraft, except where necessary for take-off or landing, or if authorised by the competent authority, regulated by Article 5 of Royal Decree 1180/2018.You can consult the above-mentioned Regulation via the link: https://www.fomento.gob.es/recursos_mfom/comodin/recursos/923_2012.pdf

Since balloons, due to their operating characteristics, do not require the infrastructure designed for the take-off and landing of aeroplanes or helicopters; and that according to point BOP.BAS.100 of Regulation (EU) 2018/395 (https://www.boe.es/doue/2018/071/L00010-00035.pdf), it is the pilot-in-command who determines whether the place for take-off or landing is suitable for the balloon and the operation to be carried out, it must be understood that events can be held in which several balloons take off from an urban area, provided that the organisation has a permit to use the public road by the municipality.