diff --git a/modules/openapi-generator/src/main/resources/python/api_client.mustache b/modules/openapi-generator/src/main/resources/python/api_client.mustache
index 3580c8ff9c6..26071c8b835 100644
--- a/modules/openapi-generator/src/main/resources/python/api_client.mustache
+++ b/modules/openapi-generator/src/main/resources/python/api_client.mustache
@@ -525,7 +525,7 @@ class ApiClient:
             if k in collection_formats:
                 collection_format = collection_formats[k]
                 if collection_format == 'multi':
-                    new_params.extend((k, str(value)) for value in v)
+                    new_params.extend((k, quote(str(value))) for value in v)
                 else:
                     if collection_format == 'ssv':
                         delimiter = ' '
diff --git a/samples/client/echo_api/python-disallowAdditionalPropertiesIfNotPresent/openapi_client/api_client.py b/samples/client/echo_api/python-disallowAdditionalPropertiesIfNotPresent/openapi_client/api_client.py
index 60d053860e3..033aa324e32 100644
--- a/samples/client/echo_api/python-disallowAdditionalPropertiesIfNotPresent/openapi_client/api_client.py
+++ b/samples/client/echo_api/python-disallowAdditionalPropertiesIfNotPresent/openapi_client/api_client.py
@@ -518,7 +518,7 @@ class ApiClient:
             if k in collection_formats:
                 collection_format = collection_formats[k]
                 if collection_format == 'multi':
-                    new_params.extend((k, str(value)) for value in v)
+                    new_params.extend((k, quote(str(value))) for value in v)
                 else:
                     if collection_format == 'ssv':
                         delimiter = ' '
diff --git a/samples/client/echo_api/python/openapi_client/api_client.py b/samples/client/echo_api/python/openapi_client/api_client.py
index 60d053860e3..033aa324e32 100644
--- a/samples/client/echo_api/python/openapi_client/api_client.py
+++ b/samples/client/echo_api/python/openapi_client/api_client.py
@@ -518,7 +518,7 @@ class ApiClient:
             if k in collection_formats:
                 collection_format = collection_formats[k]
                 if collection_format == 'multi':
-                    new_params.extend((k, str(value)) for value in v)
+                    new_params.extend((k, quote(str(value))) for value in v)
                 else:
                     if collection_format == 'ssv':
                         delimiter = ' '
diff --git a/samples/openapi3/client/petstore/python-aiohttp/petstore_api/api_client.py b/samples/openapi3/client/petstore/python-aiohttp/petstore_api/api_client.py
index 7fef2f7c0db..defe61c039f 100644
--- a/samples/openapi3/client/petstore/python-aiohttp/petstore_api/api_client.py
+++ b/samples/openapi3/client/petstore/python-aiohttp/petstore_api/api_client.py
@@ -520,7 +520,7 @@ class ApiClient:
             if k in collection_formats:
                 collection_format = collection_formats[k]
                 if collection_format == 'multi':
-                    new_params.extend((k, str(value)) for value in v)
+                    new_params.extend((k, quote(str(value))) for value in v)
                 else:
                     if collection_format == 'ssv':
                         delimiter = ' '
diff --git a/samples/openapi3/client/petstore/python/petstore_api/api_client.py b/samples/openapi3/client/petstore/python/petstore_api/api_client.py
index ae27d95bd4f..dd4d22ec6af 100755
--- a/samples/openapi3/client/petstore/python/petstore_api/api_client.py
+++ b/samples/openapi3/client/petstore/python/petstore_api/api_client.py
@@ -517,7 +517,7 @@ class ApiClient:
             if k in collection_formats:
                 collection_format = collection_formats[k]
                 if collection_format == 'multi':
-                    new_params.extend((k, str(value)) for value in v)
+                    new_params.extend((k, quote(str(value))) for value in v)
                 else:
                     if collection_format == 'ssv':
                         delimiter = ' '
diff --git a/samples/openapi3/client/petstore/python/tests/test_api_client.py b/samples/openapi3/client/petstore/python/tests/test_api_client.py
index 9567c5ca315..a84bf1b6230 100644
--- a/samples/openapi3/client/petstore/python/tests/test_api_client.py
+++ b/samples/openapi3/client/petstore/python/tests/test_api_client.py
@@ -294,3 +294,8 @@ class ApiClientTests(unittest.TestCase):
         params = self.api_client.parameters_to_url_query(params=[('list', [1, 2, 3])],
                                                          collection_formats={'list': 'multi'})
         self.assertEqual(params, "list=1&list=2&list=3")
+
+    def test_parameters_to_url_query_list_value_encoded(self):
+        params = self.api_client.parameters_to_url_query(params=[('list', [" !\"#$%&'()*+,-./:;<=>?@[\\]^_`{|}~", "2023-01-01T00:00:00+01:00"])],
+                                                         collection_formats={'list': 'multi'})
+        self.assertEqual(params, "list=%20%21%22%23%24%25%26%27%28%29%2A%2B%2C-./%3A%3B%3C%3D%3E%3F%40%5B%5C%5D%5E_%60%7B%7C%7D~&list=2023-01-01T00%3A00%3A00%2B01%3A00")
diff --git a/samples/openapi3/client/petstore/python/tests/test_api_validation.py b/samples/openapi3/client/petstore/python/tests/test_api_validation.py
index 679a3bb67b5..da1634eeceb 100644
--- a/samples/openapi3/client/petstore/python/tests/test_api_validation.py
+++ b/samples/openapi3/client/petstore/python/tests/test_api_validation.py
@@ -50,7 +50,7 @@ class ApiExceptionTests(unittest.TestCase):
         try:
             self.pet_api.get_pet_by_id()  # type: ignore
         except ValidationError as e:
-            self.assertIn("1 validation error for get_pet_by_id", str(e))
+            self.assertIn("1 validation error for PetApi.get_pet_by_id", str(e))
             self.assertIn("Missing required argument", str(e))
 
     def test_integer_validation(self):
@@ -61,7 +61,7 @@ class ApiExceptionTests(unittest.TestCase):
             # pet_id
             #   Input should be a valid integer [type=int_type, input_value='123', input_type=str]
             #     For further information visit https://errors.pydantic.dev/2.3/v/int_type
-            self.assertIn("1 validation error for get_pet_by_id", str(e))
+            self.assertIn("1 validation error for PetApi.get_pet_by_id", str(e))
             self.assertIn("Input should be a valid integer", str(e))
 
     def test_string_enum_validation(self):