[symfony 2]form don't send a file

<div id="option-action"> 
  <form  action="{{ path('lab_univer_cpanel') }}" method="post" enctype="multipart/form-data" >
  <table>
      <tr>
      <td><label>Titre</label></td>
      <td><input type="text" id="titre" name="titreNews"></td>
      <td></td>
      </tr>
      <tr>
      <td><label>Image</label></td>
      <td><input type="file" id="image" name="image" /></td>
      <td></td>
      </tr>
      <tr>
      <td><label>Contenue</label></td>
      <td><textarea  name="content" ></textarea></td>
      <td></td>
      </tr>
  <div class="submit">
      <input type="submit" name="addNews" value="+" class="addbtn">
  </div>
  </table>    
  </form>
</div>

I don't find the file image in the controller

This is the code to get request :

if ($req->request->get('addNews')) {
      $titre = $req->request->get('titreNews');
      $content = $req->request->get('content');
      $membre = $em->getRepository('LabUniverBundle:Member')
                   ->findOneBy(array('nom'=>'user'));
      $image = $req->files->get('image');
      print_r($image);

The result is a blank page ! I test with an other form like that :

<form action="{{ path('lab_univer_cpanel')}}" method="post" enctype="multipart/form-data" >
    <input type="file" name="image" />
    <input type="submit" value="send" name="checkUpload" />
</form>

It works !!!