diff --git a/Service/CustomFieldProvider.php b/Service/CustomFieldProvider.php
index d137da295..d2871560e 100644
--- a/Service/CustomFieldProvider.php
+++ b/Service/CustomFieldProvider.php
@@ -26,28 +26,46 @@ use Symfony\Component\DependencyInjection\ContainerAwareInterface;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 
 /**
- * Receive all service tagged with 'chill.custom_field'
- *
+ * Receive all the services tagged with 'chill.custom_field'.
+ * 
+ * The services tagged with 'chill.custom_field' are services used to declare
+ * a new custom field type. The tag must contain a 'type' variable (that must
+ * be unique), this type is used to identify this custom field in the form
+ * declration 
+ * 
+ * For example (in services.yml) :
+ *  services:
+ *      chill.icp2.type:
+ *          tags:
+ *              - { name: 'chill.custom_field', type: 'ICPC2' }
+ * 
  * @author Julien Fastré <julien.fastre@champs-libres.coop>
  */
 class CustomFieldProvider implements ContainerAwareInterface
 {
+    /** @var array $servicesByType The services indexes by the type */
     private $servicesByType = array();
     
-    /**
-     *
-     * @var \Symfony\Component\DependencyInjection\ContainerInterface
-     */
+    /** @var Container $container The container */
     private $container;
     
+    /**
+     * Add a new custom field to the provider
+     * 
+     * @param type $serviceName The name of the service (declared in service.yml)
+     * @param type $type The type of the service (that is used in the form to 
+     * add this type)
+     */
     public function addCustomField($serviceName, $type)
     {
         $this->servicesByType[$type] = $serviceName;
     }
     
     /**
+     * Get a custom field stored in the provider. The custom field is identified
+     * by its type.
      * 
-     * @param string $type
+     * @param string $type The type of the wanted service
      * @return CustomFieldInterface 
      */
     public function getCustomFieldByType($type)
@@ -56,10 +74,14 @@ class CustomFieldProvider implements ContainerAwareInterface
             return $this->servicesByType[$type];
         } else {
             throw new \LogicException('the custom field with type '.$type.' '
-                    . 'is not found');
+                . 'is not found');
         }
     }
 
+    /*
+     * (non-PHPdoc)
+     * @see \Symfony\Component\DependencyInjection\ContainerAwareInterface::setContainer()
+     */
     public function setContainer(ContainerInterface $container = null)
     {
         if ($container === null) {
@@ -69,9 +91,13 @@ class CustomFieldProvider implements ContainerAwareInterface
         $this->container = $container;
     }
     
+    /**
+     * Get all the custom fields known by the provider
+     * 
+     * @return array Array of the known custom fields indexed by the type.
+     */
     public function getAllFields()
     {
         return $this->servicesByType;
     }
-
 }