diff --git a/modules/openapi-generator/src/main/resources/python-pydantic-v1/api_client.mustache b/modules/openapi-generator/src/main/resources/python-pydantic-v1/api_client.mustache
index 000b6658b131..244474c13c6f 100644
--- a/modules/openapi-generator/src/main/resources/python-pydantic-v1/api_client.mustache
+++ b/modules/openapi-generator/src/main/resources/python-pydantic-v1/api_client.mustache
@@ -220,6 +220,12 @@ class ApiClient:
                                                      collection_formats)
             url += "?" + url_query
 
+        def extract_charset(content_type):
+            match = None
+            if content_type is not None:
+                match = re.search(r"charset=([a-zA-Z\-\d]+)[\s;]?", content_type)
+            return match.group(1) if match else "utf-8"
+
         try:
             # perform request and return response
             response_data = {{#asyncio}}await {{/asyncio}}{{#tornado}}yield {{/tornado}}self.request(
@@ -231,7 +237,12 @@ class ApiClient:
                 _request_timeout=_request_timeout)
         except ApiException as e:
             if e.body:
-                e.body = e.body.decode('utf-8')
+                try:
+                    charset = extract_charset((e.headers or {}).get('content-type'))
+                    e.body = e.body.decode(charset)
+                except UnicodeDecodeError:
+                    # Keep original body if charset is not recognized.
+                    pass
             raise e
 
         self.last_response = response_data
@@ -247,12 +258,9 @@ class ApiClient:
           if response_type == "bytearray":
               response_data.data = response_data.data
           else:
-              match = None
               content_type = response_data.getheader('content-type')
-              if content_type is not None:
-                  match = re.search(r"charset=([a-zA-Z\-\d]+)[\s;]?", content_type)
-              encoding = match.group(1) if match else "utf-8"
-              response_data.data = response_data.data.decode(encoding)
+              charset = extract_charset(content_type)
+              response_data.data = response_data.data.decode(charset)
 
           # deserialize response data
           if response_type == "bytearray":
diff --git a/samples/client/echo_api/python-pydantic-v1/openapi_client/api_client.py b/samples/client/echo_api/python-pydantic-v1/openapi_client/api_client.py
index 6d0d11c5b538..13e5efa0481d 100644
--- a/samples/client/echo_api/python-pydantic-v1/openapi_client/api_client.py
+++ b/samples/client/echo_api/python-pydantic-v1/openapi_client/api_client.py
@@ -207,6 +207,12 @@ def __call_api(
                                                      collection_formats)
             url += "?" + url_query
 
+        def extract_charset(content_type):
+            match = None
+            if content_type is not None:
+                match = re.search(r"charset=([a-zA-Z\-\d]+)[\s;]?", content_type)
+            return match.group(1) if match else "utf-8"
+
         try:
             # perform request and return response
             response_data = self.request(
@@ -218,7 +224,12 @@ def __call_api(
                 _request_timeout=_request_timeout)
         except ApiException as e:
             if e.body:
-                e.body = e.body.decode('utf-8')
+                try:
+                    charset = extract_charset((e.headers or {}).get('content-type'))
+                    e.body = e.body.decode(charset)
+                except UnicodeDecodeError:
+                    # Keep original body if charset is not recognized.
+                    pass
             raise e
 
         self.last_response = response_data
@@ -234,12 +245,9 @@ def __call_api(
           if response_type == "bytearray":
               response_data.data = response_data.data
           else:
-              match = None
               content_type = response_data.getheader('content-type')
-              if content_type is not None:
-                  match = re.search(r"charset=([a-zA-Z\-\d]+)[\s;]?", content_type)
-              encoding = match.group(1) if match else "utf-8"
-              response_data.data = response_data.data.decode(encoding)
+              charset = extract_charset(content_type)
+              response_data.data = response_data.data.decode(charset)
 
           # deserialize response data
           if response_type == "bytearray":
diff --git a/samples/openapi3/client/petstore/python-pydantic-v1-aiohttp/petstore_api/api_client.py b/samples/openapi3/client/petstore/python-pydantic-v1-aiohttp/petstore_api/api_client.py
index 52390c675df6..c61be95af42b 100644
--- a/samples/openapi3/client/petstore/python-pydantic-v1-aiohttp/petstore_api/api_client.py
+++ b/samples/openapi3/client/petstore/python-pydantic-v1-aiohttp/petstore_api/api_client.py
@@ -187,6 +187,12 @@ async def __call_api(
                                                      collection_formats)
             url += "?" + url_query
 
+        def extract_charset(content_type):
+            match = None
+            if content_type is not None:
+                match = re.search(r"charset=([a-zA-Z\-\d]+)[\s;]?", content_type)
+            return match.group(1) if match else "utf-8"
+
         try:
             # perform request and return response
             response_data = await self.request(
@@ -198,7 +204,12 @@ async def __call_api(
                 _request_timeout=_request_timeout)
         except ApiException as e:
             if e.body:
-                e.body = e.body.decode('utf-8')
+                try:
+                    charset = extract_charset((e.headers or {}).get('content-type'))
+                    e.body = e.body.decode(charset)
+                except UnicodeDecodeError:
+                    # Keep original body if charset is not recognized.
+                    pass
             raise e
 
         self.last_response = response_data
@@ -214,12 +225,9 @@ async def __call_api(
           if response_type == "bytearray":
               response_data.data = response_data.data
           else:
-              match = None
               content_type = response_data.getheader('content-type')
-              if content_type is not None:
-                  match = re.search(r"charset=([a-zA-Z\-\d]+)[\s;]?", content_type)
-              encoding = match.group(1) if match else "utf-8"
-              response_data.data = response_data.data.decode(encoding)
+              charset = extract_charset(content_type)
+              response_data.data = response_data.data.decode(charset)
 
           # deserialize response data
           if response_type == "bytearray":
diff --git a/samples/openapi3/client/petstore/python-pydantic-v1/petstore_api/api_client.py b/samples/openapi3/client/petstore/python-pydantic-v1/petstore_api/api_client.py
index fae62ad75768..ede41232a231 100644
--- a/samples/openapi3/client/petstore/python-pydantic-v1/petstore_api/api_client.py
+++ b/samples/openapi3/client/petstore/python-pydantic-v1/petstore_api/api_client.py
@@ -206,6 +206,12 @@ def __call_api(
                                                      collection_formats)
             url += "?" + url_query
 
+        def extract_charset(content_type):
+            match = None
+            if content_type is not None:
+                match = re.search(r"charset=([a-zA-Z\-\d]+)[\s;]?", content_type)
+            return match.group(1) if match else "utf-8"
+
         try:
             # perform request and return response
             response_data = self.request(
@@ -217,7 +223,12 @@ def __call_api(
                 _request_timeout=_request_timeout)
         except ApiException as e:
             if e.body:
-                e.body = e.body.decode('utf-8')
+                try:
+                    charset = extract_charset((e.headers or {}).get('content-type'))
+                    e.body = e.body.decode(charset)
+                except UnicodeDecodeError:
+                    # Keep original body if charset is not recognized.
+                    pass
             raise e
 
         self.last_response = response_data
@@ -233,12 +244,9 @@ def __call_api(
           if response_type == "bytearray":
               response_data.data = response_data.data
           else:
-              match = None
               content_type = response_data.getheader('content-type')
-              if content_type is not None:
-                  match = re.search(r"charset=([a-zA-Z\-\d]+)[\s;]?", content_type)
-              encoding = match.group(1) if match else "utf-8"
-              response_data.data = response_data.data.decode(encoding)
+              charset = extract_charset(content_type)
+              response_data.data = response_data.data.decode(charset)
 
           # deserialize response data
           if response_type == "bytearray":