diff --git a/gobject/ChangeLog b/gobject/ChangeLog
index 983d63445..f5a391dc2 100644
--- a/gobject/ChangeLog
+++ b/gobject/ChangeLog
@@ -1,3 +1,10 @@
+2008-02-06  Benjamin Otte  <otte@gnome.org>
+
+	* gparamspecs.c: (param_gtype_set_default), (param_gtype_validate):
+	make GParamGType require the set type during construction instead of
+	using G_TYPE_NONE, which causes issues when setting.
+	Bug 513073 - g_param_spec_gtype breaks with G_PARAM_CONSTRUCT
+
 2008-02-05 18:52:07  Tim Janik  <timj@imendio.com>
 
 	* gtype.c: added recursive mutex to protect class initialization,
diff --git a/gobject/gparamspecs.c b/gobject/gparamspecs.c
index 30c744b0e..5cbe6054a 100644
--- a/gobject/gparamspecs.c
+++ b/gobject/gparamspecs.c
@@ -1042,7 +1042,9 @@ static void
 param_gtype_set_default (GParamSpec *pspec,
 			 GValue     *value)
 {
-  value->data[0].v_long = G_TYPE_NONE;
+  GParamSpecGType *tspec = G_PARAM_SPEC_GTYPE (pspec);
+
+  value->data[0].v_long = tspec->is_a_type;
 }
 
 static gboolean
@@ -1055,7 +1057,7 @@ param_gtype_validate (GParamSpec *pspec,
   
   if (tspec->is_a_type != G_TYPE_NONE && !g_type_is_a (gtype, tspec->is_a_type))
     {
-      value->data[0].v_long = G_TYPE_NONE;
+      value->data[0].v_long = tspec->is_a_type;
       changed++;
     }