The column id must be mapped to a field - php

Question

Just changed some setting to a doctrine entity configuration and got the following execption
The column id must be mapped to a field in class VSmart\OrmBundle\Entity\Ob
ject since it is referenced by a join column of another class.
I would expect that the column id is not mapped to a field in Object. Though, see here the code of that particular mapping:
/**
* #var integer
*
* #ORM\Column(name="Id", type="integer", nullable=false)
* #ORM\Id
* #ORM\GeneratedValue(strategy="IDENTITY")
*/
private $id;
So, what is the exception really trying to tell me?
Update
This is the other end of the relation.
Object definition:
/**
* #var integer
*
* #ORM\Column(name="Id", type="integer", nullable=false)
* #ORM\Id
* #ORM\GeneratedValue(strategy="IDENTITY")
*/
private $id;
/**
* #var string
*
* #ORM\Column(name="Address", type="string", length=45, nullable=true)
*/
private $address;
/**
* #var string
*
* #ORM\Column(name="Name", type="string", length=45, nullable=true)
*/
private $name;
/**
* #var \Entis
*
* #ORM\ManyToOne(targetEntity="Entis",inversedBy="objects")
* #ORM\JoinColumns({
* #ORM\JoinColumn(name="EntisId", referencedColumnName="Id")
* })
*/
private $entis;
/**
* #var \Objecttype
*
* #ORM\ManyToOne(targetEntity="ObjectType")
* #ORM\JoinColumns({
* #ORM\JoinColumn(name="ObjectType", referencedColumnName="Id")
* })
*/
private $objectType;
/**
* #var \Unit
*
* #ORM\ManyToOne(targetEntity="Unit")
* #ORM\JoinColumns({
* #ORM\JoinColumn(name="UnitId", referencedColumnName="Id")
* })
*/
private $unit;
/**
* #var \Dimension
*
* #ORM\ManyToOne(targetEntity="Dimension")
* #ORM\JoinColumns({
* #ORM\JoinColumn(name="DimensionId", referencedColumnName="Id")
* })
*/
private $dimension;
/**
* #ORM\ManyToMany(targetEntity="Tag") */
private $tags;
/**
* #ORM\OneToMany(targetEntity="Measurement", mappedBy="object")
*/
private $measurements;