diff --git a/rules.lua b/rules.lua
index 0134d9a..bcb029d 100644
--- a/rules.lua
+++ b/rules.lua
@@ -39,9 +39,9 @@ awful.rules.rules = {
       properties = { tag = tags[rule_screen][4] } },
     { rule = { instance = "Gmutt" },
       properties = { tag = tags[rule_screen][4] } },
-    { rule = { class = "Gcanto" },
+    { rule = { instance = "Gcanto" },
       properties = { tag = tags[rule_screen][5] } },
-    { rule = { class = "Gncmpcpp" },
+    { rule = { instance = "Gncmpcpp" },
       properties = { tag = tags[rule_screen][6] } },
     { rule = { class = "Gmpc" },
       properties = { tag = tags[rule_screen][6] } },