diff --git a/CommentForm.php b/CommentForm.php
index c9b7469..64c4ab8 100644
--- a/CommentForm.php
+++ b/CommentForm.php
@@ -61,6 +61,25 @@ public function init()
                 )
             );
 
+        // The legal agreement is checked by default for logged users.
+        if (get_option('commenting_legal_text')) {
+            $this->addElement('checkbox', 'commenting_legal_text', array(
+                'label' => get_option('commenting_legal_text'),
+                'value' => (boolean) $user,
+                'required' => true,
+                'uncheckedValue'=> '',
+                'checkedValue' => 'checked',
+                'validators' => array(
+                    array('notEmpty', true, array(
+                        'messages' => array(
+                            'isEmpty'=> __('You must agree to the terms and conditions.'),
+                        ),
+                    )),
+                ),
+                'decorators' => array('ViewHelper', 'Errors', array('label', array('escape' => false))),
+            ));
+        }
+
         $request = Zend_Controller_Front::getInstance()->getRequest();
         $params = $request->getParams();
 
@@ -135,4 +154,4 @@ private function _getRecordType($params)
         return $model;
     }
 
-}
\ No newline at end of file
+}
diff --git a/CommentingPlugin.php b/CommentingPlugin.php
index f399ac9..c9557ac 100644
--- a/CommentingPlugin.php
+++ b/CommentingPlugin.php
@@ -27,6 +27,13 @@ class CommentingPlugin extends Omeka_Plugin_AbstractPlugin
         'api_extend_collections'
     );
 
+    /**
+     * @var array Options and their default values.
+     */
+    protected $_options = array(
+        'commenting_legal_text' => '',
+    );
+
     /**
      * Add the translations.
      */
@@ -78,6 +85,15 @@ public function hookInstall()
         set_option('commenting_reqapp_comment_roles', serialize(array()));
         set_option('commenting_view_roles', serialize(array()));
 
+        $html = '<p>';
+        $html .= __('I agree with %s terms of use %s and I accept to free my contribution under the licence %s CC BY-SA %s.',
+            '<a href="#" target="_blank">', '</a>',
+            '<a href="https://creativecommons.org/licenses/by-sa/3.0/" target="_blank">', '</a>'
+        );
+        $html .= '</p>';
+        $this->_options['commenting_legal_text'] = $html;
+
+        $this->_installOptions();
     }
 
     public function hookUpgrade($args)
diff --git a/config_form.php b/config_form.php
index 31c74b2..a047c0b 100644
--- a/config_form.php
+++ b/config_form.php
@@ -1,3 +1,12 @@
+<?php echo js_tag('vendor/tiny_mce/tiny_mce'); ?>
+<script type="text/javascript">
+jQuery(window).load(function () {
+  Omeka.wysiwyg({
+    mode: 'specific_textareas',
+    editor_selector: 'html-editor'
+  });
+});
+</script>
 <script type='text/javascript'>
 <?php include('config_form.js'); ?>
 </script>
@@ -30,7 +39,30 @@
             </div>        
         </div>
     </div>    
-    
+
+    <div class='field'>
+        <div class="two columns alpha">
+            <label><?php echo __('Legal agreement'); ?></label>
+        </div>
+        <div class='inputs five columns omega'>
+            <div class='input-block'>
+                <?php echo $view->formTextarea(
+                    'commenting_legal_text',
+                    get_option('commenting_legal_text'),
+                    array(
+                        'rows' => 5,
+                        'cols' => 60,
+                        'class' => array('textinput', 'html-editor')
+                     )
+                ); ?>
+                <p class="explanation">
+                    <?php echo __('This text will be shown beside the legal checkbox.'
+                        . " Let empty if you don't want to use a legal agreement."); ?>
+                </p>
+            </div>
+        </div>
+    </div>
+
     <div class="field">
         <div class="three columns alpha">
             <label><?php echo __("Allow public commenting?"); ?></label>