diff --git a/src/paho/mqtt/client.py b/src/paho/mqtt/client.py
index f5897328..94cad80d 100644
--- a/src/paho/mqtt/client.py
+++ b/src/paho/mqtt/client.py
@@ -953,7 +953,7 @@ def protocol(self) -> MQTTProtocolVersion:
 
         This property is read-only.
         """
-        return self.protocol
+        return self._protocol
 
     @property
     def connect_timeout(self) -> float: