diff --git a/influxdb_client/client/_base.py b/influxdb_client/client/_base.py
index 8dcf75e9..d4f17901 100644
--- a/influxdb_client/client/_base.py
+++ b/influxdb_client/client/_base.py
@@ -53,6 +53,8 @@ def __init__(self, url, token, debug=None, timeout=10_000, enable_gzip=False, or
         self.default_tags = default_tags
 
         self.conf = _Configuration()
+        if not isinstance(self.url, str):
+            raise ValueError('"url" attribute is not str instance')
         if self.url.endswith("/"):
             self.conf.host = self.url[:-1]
         else: