diff --git a/include/mqtt_client.h b/include/mqtt_client.h
index 2b40a22..8fb5b8c 100644
--- a/include/mqtt_client.h
+++ b/include/mqtt_client.h
@@ -462,7 +462,7 @@ esp_err_t esp_mqtt_client_stop(esp_mqtt_client_handle_t client);
  *         -2 in case of full outbox.
  */
 #define esp_mqtt_client_subscribe(client_handle, topic_type, qos_or_size) _Generic((topic_type), \
-      char *: esp_mqtt_client_subscribe_single, \
+      const char *: esp_mqtt_client_subscribe_single, \
       esp_mqtt_topic_t*: esp_mqtt_client_subscribe_multiple \
     )(client_handle, topic_type, qos_or_size)