diff --git a/core/lib/Drupal/Core/Config/Config.php b/core/lib/Drupal/Core/Config/Config.php
index d354799..b1b329a 100644
--- a/core/lib/Drupal/Core/Config/Config.php
+++ b/core/lib/Drupal/Core/Config/Config.php
@@ -56,6 +56,11 @@ class Config extends StorableConfigBase {
   /**
    * Constructs a configuration object.
    *
+   * A valid name must :
+   * - Be namespaced by its owner (i.e. contain at least one '.').
+   * - Be shorter than Config::MAX_LENGTH characters.
+   * - Not contain any of the following characters: ? : * < > " ' / \
+   *
    * @param string $name
    *   The name of the configuration object being constructed.
    * @param \Drupal\Core\Config\StorageInterface $storage
@@ -67,6 +72,9 @@ class Config extends StorableConfigBase {
    *   The typed configuration manager service.
    */
   public function __construct($name, StorageInterface $storage, EventDispatcherInterface $event_dispatcher, TypedConfigManagerInterface $typed_config) {
+    
+    // Validate the configuration object name.
+    static::validateName($name);
     $this->name = $name;
     $this->storage = $storage;
     $this->eventDispatcher = $event_dispatcher;
@@ -204,8 +212,6 @@ public function clear($key) {
    * {@inheritdoc}
    */
   public function save() {
-    // Validate the configuration object name before saving.
-    static::validateName($this->name);
 
     // If there is a schema for this configuration object, cast all values to
     // conform to the schema.