Index taxonomy terms numerically (EU version)

<?php

// Add the following to your (child) theme's functions.php and re-index afterwards

add_filter( 'facetwp_index_row', function( $params, $class ) {
    if ( 'alcohol' == $params['facet_name'] ) {
        $value = $params['facet_display_value'];

        // Swap "," and "." since this is EU-based number format
        $value = str_replace( ',', '{comma}', $value );
        $value = str_replace( '.', ',', $value );
        $value = str_replace( '{comma}', '.', $value );

        $params['facet_value'] = $value;
        $params['facet_display_value'] = $value;
    }

    return $params;
}, 10, 2 );