Workaround to pass a given currency to Eventbrite when using Modern Tribe's The Events Calendar: Eventbrite Tickets plugin.

functions.php

<?php
/* PLACE THE FOLLOWING IN YOUR THEME'S FUNCTIONS.PHP FILE. */

add_action( 'tribe_eb_after_event_creation', 'my_change_tribe_eventbrite_currency', 10, 4 );

function my_change_tribe_eventbrite_currency( $eventbrite_id, $venue_id, $organizer_id, $post_id ) {
	// See http://www.currencysystem.com/codes/ for a list of three-letter
	// currency acronyms. Change the below variable to your preference.
	$currency_acro = 'EUR';
	
	$parameters = 'id=' . $eventbrite_id . '&currency=' . $currency_acro;
	
	$success = Event_Tickets_PRO::sendEventBriteRequest( 'event_update', $parameters, $post_id, true, true, false );
	
	if ( !$success ) {
		add_filter( 'tribe_eb_error_message', 'my_change_tribe_eventbrite_currency_failed' );
	}
}

function my_change_tribe_eventbrite_currency_failed() {
	return 'Failed to update the currency.';
}