diff --git a/gdk/gdkcontentdeserializer.c b/gdk/gdkcontentdeserializer.c
index 18cf043790..ba0908a47e 100644
--- a/gdk/gdkcontentdeserializer.c
+++ b/gdk/gdkcontentdeserializer.c
@@ -364,7 +364,7 @@ gdk_content_deserializer_return_success (GdkContentDeserializer *deserializer)
 /**
  * gdk_content_deserializer_return_error:
  * @deserializer: a `GdkContentDeserializer`
- * @error: a `GError`
+ * @error: (transfer full): a `GError`
  *
  * Indicate that the deserialization has ended with an error.
  *
diff --git a/gdk/gdkcontentserializer.c b/gdk/gdkcontentserializer.c
index 525f32475c..29f9b2d203 100644
--- a/gdk/gdkcontentserializer.c
+++ b/gdk/gdkcontentserializer.c
@@ -368,7 +368,7 @@ gdk_content_serializer_return_success (GdkContentSerializer *serializer)
 /**
  * gdk_content_serializer_return_error:
  * @serializer: a `GdkContentSerializer`
- * @error: a `GError`
+ * @error: (transfer full): a `GError`
  *
  * Indicate that the serialization has ended with an error.
  *