diff --git a/src/plugins/fset/fset-option.c b/src/plugins/fset/fset-option.c
index f638052b3..3f0be2ced 100644
--- a/src/plugins/fset/fset-option.c
+++ b/src/plugins/fset/fset-option.c
@@ -1640,7 +1640,7 @@ fset_option_print_log ()
             continue;
         weechat_log_printf ("");
         weechat_log_printf ("[fset option (addr:0x%lx)]", ptr_fset_option);
-        weechat_log_printf ("  index . . . . . . . . : '%s'",  ptr_fset_option->index);
+        weechat_log_printf ("  index . . . . . . . . : %d",    ptr_fset_option->index);
         weechat_log_printf ("  file. . . . . . . . . : '%s'",  ptr_fset_option->file);
         weechat_log_printf ("  section . . . . . . . : '%s'",  ptr_fset_option->section);
         weechat_log_printf ("  option. . . . . . . . : '%s'",  ptr_fset_option->option);