/**
 * Contacts
 *
 * @ORMTable(name="contacts")
 * @ORMEntity(repositoryClass="AppBundleRepositoryContactsRepository")
 */
class Contacts
{
....

/**
 * @var DoctrineCommonCollectionsCollection
 *
 * @ORMManyToMany(targetEntity="AppBundleEntityMedias", inversedBy="contact")
 * @ORMJoinTable(name="contacts_has_medias",
 *   joinColumns={
 *     @ORMJoinColumn(name="contact_id", referencedColumnName="id")
 *   },
 *   inverseJoinColumns={
 *     @ORMJoinColumn(name="media_id", referencedColumnName="id")
 *   }
 * )
 */
private $media;

....

class ContactsRepository extends EntityRepository
{

public function getContacts()
{
  return $this->getEntityManager()
    ->createQuery(
        'SELECT c FROM AppBundle:Contact c ORDER BY c.Name ASC'
    )
    ->getResult();
}

public function getContact($idContact)
{

    $qb = $this->createQueryBuilder('c')
      ->andWhere('c.id = :idContact')
      ->setParameter('idContact', $idContact);

    $query = $qb->getQuery();
    return $query->execute();

}
}

/**
 * Medias
 *
 * @ORMTable(name="medias")
 * @ORMEntity
 */

class Medias
{

/**
 * @var integer
 *
 * @ORMColumn(name="id", type="integer")
 * @ORMId
 * @ORMGeneratedValue(strategy="IDENTITY")
 */
private $id;

/**
 * @var string
 *
 * @ORMOneToMany(targetEntity="AppBundleEntityCharges", mappedBy="media", cascade={"ALL"}, indexBy="contact")
 */
private $charge;

....

/**
 * Charges
 *
 * @ORMTable(name="charges")
 * @ORMEntity
 * @UniqueEntity(fields={"contact_id", "media_id"})
 */
class Charges
{
/**
 * @var string
 *
 * @ORMColumn(name="charge", type="string", length=255, nullable=true)
 */
private $charge;

/**
 * @ORMId
 * @ORMManyToOne(targetEntity="AppBundleEntityContacts")
 * @ORMGeneratedValue(strategy="NONE")
 */
private $contact;

/**
 * @ORMId
 * @ORMManyToOne(targetEntity="AppBundleEntityMedias", inversedBy="charge")
 * @ORMGeneratedValue(strategy="NONE")
 */
private $media;

public function __construct(Contact $contact, Media $media, $charge)
{
    $this->media = $media;
    $this->contact = $contact;
    $this->charge = $charge;
}
}