config_prod.yml

#...
parameters:
    exception_listener.controller: "YourBundle:Exception:exception"

ExceptionController.php

<?php
namespace Application\YourBundle\Controller;

use Symfony\Bundle\FrameworkBundle\Controller\Controller;
use Symfony\Component\HttpKernel\Exception\FlattenException;
use Symfony\Component\HttpKernel\Log\DebugLoggerInterface;

class ExceptionController extends Controller
{
    /**
     * Converts an Exception to a Response.
     *
     * @param FlattenException     $exception A FlattenException instance
     * @param DebugLoggerInterface $logger    A DebugLoggerInterface instance
     * @param string               $format    The format to use for rendering (html, xml, ...)
     * @param Boolean              $embedded  Whether the rendered Response will be embedded or not
     *
     * @throws \InvalidArgumentException When the exception template does not exist
     */
    public function exceptionAction(FlattenException $exception, DebugLoggerInterface $logger = null, $format = 'html', $embedded = false)
    {
        
        switch($exception->getCode()){
            case 404:
                $tpl = '404';
            break;
            default: 
                $tpl = 'error';
            break;   
        }
        // for example of course :)
        return $this->render('YourBundle:Exception:'.$tpl.'.php', array(
            'exception' => $exception,
        ));
    }

}