Articles 53 & 54 of the VAT Directive include a specific guideline for (international) events, stating VAT must be charged in the country where the actual event takes place.
Business to customers (B2C) services relating to cultural, artistic, sporting, scientific, educational, entertainment, and similar activities will be taxed at the place where those activities actually take place [Article 54 of the VAT Directive].
Business to business (B2B) services in respect of admission to cultural, artistic, sporting, scientific, educational, entertainment, and similar events will be taxed at the place where those events actually take place [Article 53 of the VAT Directive].
Please refer to your tax advisors to check if/how this tax can be (partially) reclaimed.