diff --git a/components/FreeNetwork/FreeNetwork.php b/components/FreeNetwork/FreeNetwork.php
index 0bb90380c7..2798cffabc 100644
--- a/components/FreeNetwork/FreeNetwork.php
+++ b/components/FreeNetwork/FreeNetwork.php
@@ -500,11 +500,16 @@ class FreeNetwork extends Component
         return false;
     }
 
-    public static function mentionToName(string $nickname, string $uri): string
+    public static function mentionTagToName(string $nickname, string $uri): string
     {
         return '@' . $nickname . '@' . parse_url($uri, \PHP_URL_HOST);
     }
 
+    public static function groupTagToName(string $nickname, string $uri): string
+    {
+        return '!' . $nickname . '@' . parse_url($uri, \PHP_URL_HOST);
+    }
+
     public function onPluginVersion(array &$versions): bool
     {
         $versions[] = [
diff --git a/plugins/ActivityPub/Util/Model/Note.php b/plugins/ActivityPub/Util/Model/Note.php
index 713eeb8584..35a3e4e5f0 100644
--- a/plugins/ActivityPub/Util/Model/Note.php
+++ b/plugins/ActivityPub/Util/Model/Note.php
@@ -390,11 +390,19 @@ class Note extends Model
 
         // Mentions
         foreach ($object->getNotificationTargets() as $mention) {
-            $attr['tag'][] = [
-                'type' => 'Mention',
-                'href' => ($href = $mention->getUri()),
-                'name' => FreeNetwork::mentionToName($mention->getNickname(), $href),
-            ];
+            if ($mention->isGroup()) {
+                $attr['tag'][] = [
+                    'type' => 'Group',
+                    'href' => ($href = $mention->getUri()),
+                    'name' => FreeNetwork::groupTagToName($mention->getNickname(), $href),
+                ];
+            } else {
+                $attr['tag'][] = [
+                    'type' => 'Mention',
+                    'href' => ($href = $mention->getUri()),
+                    'name' => FreeNetwork::mentionTagToName($mention->getNickname(), $href),
+                ];
+            }
             $attr['to'][] = $href;
         }
 
diff --git a/src/Twig/Runtime.php b/src/Twig/Runtime.php
index 63c0ef3ae2..bb1007141e 100644
--- a/src/Twig/Runtime.php
+++ b/src/Twig/Runtime.php
@@ -199,10 +199,18 @@ class Runtime implements RuntimeExtensionInterface, EventSubscriberInterface
 
     public function mention(Actor $actor): string
     {
-        if ($actor->getIsLocal()) {
-            return "@{$actor->getNickname()}";
+        if ($actor->isGroup()) {
+            if ($actor->getIsLocal()) {
+                return "!{$actor->getNickname()}";
+            } else {
+                return FreeNetwork::groupTagToName($actor->getNickname(), $actor->getUri(type: Router::ABSOLUTE_URL));
+            }
         } else {
-            return FreeNetwork::mentionToName($actor->getNickname(), $actor->getUri(type: Router::ABSOLUTE_URL));
+            if ($actor->getIsLocal()) {
+                return "@{$actor->getNickname()}";
+            } else {
+                return FreeNetwork::mentionTagToName($actor->getNickname(), $actor->getUri(type: Router::ABSOLUTE_URL));
+            }
         }
     }