Doctrine - Empty proxy object values

Client.class.php

namespace Model\Entities;

use Doctrine\Common\Collections\ArrayCollection;

class Client extends Entreprise
{
    function __construct($id = null, $nom = null) {
        parent::__construct($id, $nom);
    } 
}

Entity.class.php

namespace Model\Entities;

abstract class Entity
{
    private function processToArray($attributes, $maxDepth, $depth = 0)
    {
        //....
    }

    private function processArray($array, $maxDepth, $depth)
    {
        //...
    }

    public function toArray($attributes = null, $maxDepth = 1)
    {
        //...
    }
}

Entreprise.class.php

namespace Model\Entities;
class Entreprise extends Entity
{
    /**
    * Identifiant de l'entreprise.
    * @var int
    * @Id @Column(type="integer") @GeneratedValue
    */
    protected $id;

    /**
    * Nom de l'entreprise.
    * @var string
    * @Column(type="string")
    */
    protected $nom;

    function __construct($id = null, $nom = null) {
        if (!empty($id)) $this->setId($id);
        if (!empty($nom)) $this->setNom($nom);
    }

    public function getId()
    {
        return $this->id;
    }

    public function getNom()
    {
        return $this->nom;
    }

    public function setId($id)
    {
        if ($id === null || is_int($id)) {
            $this->id = $id;
        } else {
            throw new \Lib\ParameterException('identifiant d\'entreprise est un int');
        }
    }


    public function setNom($nom)
    {
        if ($nom === null || is_string($nom)) {
            $this->nom = $nom;
        } else {
            throw new \Lib\ParameterException('nom d\'entreprise est une string');
        }
    }
}

ModelEntitiesClientProxy.class.php

namespace Proxies;

/**
* THIS CLASS WAS GENERATED BY THE DOCTRINE ORM. DO NOT EDIT THIS FILE.
*/
class ModelEntitiesClientProxy extends \Model\Entities\Client implements \Doctrine\ORM\Proxy\Proxy
{
    private $_entityPersister;
    private $_identifier;
    public $__isInitialized__ = false;

    public function __construct($entityPersister, $identifier)
    {
        $this->_entityPersister = $entityPersister;
        $this->_identifier = $identifier;
    }

    private function _load()
    {
        if (!$this->__isInitialized__ && $this->_entityPersister) {
            $this->__isInitialized__ = true;
            if ($this->_entityPersister->load($this->_identifier, $this) === null) {
                throw new \Doctrine\ORM\EntityNotFoundException();
            }
            unset($this->_entityPersister, $this->_identifier);
        }
    }

    public function setId($id)
    {
        $this->_load();
        return parent::setId($id);
    }

    public function setNom($nom)
    {
        $this->_load();
        return parent::setNom($nom);
    }

    public function getId()
    {
        $this->_load();
        return parent::getId();
    }

    public function getNom()
    {
        $this->_load();
        return parent::getNom();
    }

    public function setId($id)
    {
        $this->_load();
        return parent::setId($id);
    }

    public function setNom($nom)
    {
        $this->_load();
        return parent::setNom($nom);
    }

    public function __toString()
    {
        $this->_load();
        return parent::__toString();
    }

    public function toArray($attributes = NULL, $maxDepth = 1)
    {
        $this->_load();
        return parent::toArray($attributes, $maxDepth);
    }

    public function __sleep()
    {
        return array('__isInitialized__', 'id', 'nom');
    }

    public function __clone()
    {
        if (!$this->__isInitialized__ && $this->_entityPersister) {
            $this->__isInitialized__ = true;
            $class = $this->_entityPersister->getClassMetadata();
            $original = $this->_entityPersister->load($this->_identifier);
            if ($original === null) {
                throw new \Doctrine\ORM\EntityNotFoundException();
            }
            foreach ($class->reflFields AS $field => $reflProperty) {
                $reflProperty->setValue($this, $reflProperty->getValue($original));
            }
            unset($this->_entityPersister, $this->_identifier);
        }
    }
}

Projet.class.php

namespace Model\Entities;
use Doctrine\Common\Collections\ArrayCollection;
class Projet extends Entity
{
    /**
    * Identifiant du projet.
    * @var int
    * @Id @Column(type="integer") @GeneratedValue
    */
    protected $id;


    /**
    * Client du projet.
    * @var \Model\Entities\Client
    * @ManyToOne(targetEntity="Client")
    */
    protected $client;

    /**
    * Titre du projet.
    * @var string
    * @Column(type="string")
    */
    protected $titre;

    function __construct($id = null, Client $client = null, $titre = null)
    {
        if (!empty($id)) $this->setId($id);
        if (!empty($client)) $this->setClient($client);
        if (!empty($titre)) $this->setTitre($titre);
    }

    public function setVals($projet)
    {
        die('>'.$projet.'<'); // -- (B)
    }

    public function getId()
    {
        return $this->id;
    }

    public function getClient()
    {
        return $this->client;
    }

    public function getTitre()
    {
        return $this->titre;
    }

    public function setId($id)
    {
        if ($id === null || is_int($id)) {
            $this->id = $id;
        } else {
            throw new \Lib\ParameterException('identifiant de personne est un int');
        }
    }

    public function setClient($client)
    {
        if ($client === null || $client instanceof Client) {
            $this->client = $client;
        } else {
            throw new \Lib\ParameterException('client de projet est un \Model\Entities\Client');
        }
    }

    public function setTitre($titre)
    {
        if ($titre === null || is_string($titre)) {
            $this->titre = $titre;
        } else {
            throw new \Lib\ParameterException('titre de projet est une string');
        }
    }

    public function __toString() {
        return get_class($this) . " || Id: " . $this->getId() . ", Clientid: " . $this->getClient()->getId();
    }
}

ProjetManager.class.php

namespace Model\Managers;

class ProjetManager extends \Doctrine\ORM\EntityRepository
{
    public function modifier($guid, \Model\Entities\Projet $projet)
    {
        $em = $this->getEntityManager();
        $projetAModifier = $em->find('\Model\Entities\Projet', $guid);
        // die($projet); --- (A)
        $projetAModifier->setVals($projet);
    }
}