DQL on ManyToMany relationship : multiple where parameters - doctrine-orm

Question

I have 2 entities with a relation ManyToMany
class User{
/**
* Owning Side
*
* #ORM\ManyToMany(targetEntity="Aire\AppBundle\Entity\Project", inversedBy="projectFollowed")
* #ORM\JoinTable(name="project_followed",
* joinColumns={#ORM\JoinColumn(name="user_id", referencedColumnName="id")},
* inverseJoinColumns={#ORM\JoinColumn(name="project_id", referencedColumnName="id")}
* )
**/
private $projectFollowed;
}
class Project{
/**
* Inverse Side
*
* #ORM\ManyToMany(targetEntity="Application\Sonata\UserBundle\Entity\User", mappedBy="projectFollowed")
**/
private $projectFollowed;
}
I need to check in my project_followed table if there is already a user assigned to this project.
$dql = '
SELECT user
FROM Application\Sonata\UserBundle\Entity\User user
INNER JOIN user.projectFollowed project_followed
WHERE project_followed.project_id = :project_id
AND project_followed.user_id = :user_id
';
$em = $this->getDoctrine()->getManager();
$query = $em
->createQuery( $dql )
->setParameter( 'project_id', $project_id )
->setParameter( 'user_id', $user_id )
;
It seems my DQL is not correct :
Class AppBundle\Entity\Project has no field or association named project_id
So if i change
WHERE project_followed.project_id = :project_id
to
WHERE project_followed.id = :project_id
It is working but how can i make the relation with the user id?
The reason of this is because i need to check if there is no duplicate entries.