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 fd3d0b8a200..63ad0f1f8f7 100644
--- a/modules/openapi-generator/src/main/resources/python/api_client.mustache
+++ b/modules/openapi-generator/src/main/resources/python/api_client.mustache
@@ -10,6 +10,7 @@ import os
 import re
 import typing
 from urllib.parse import quote
+from urllib3.fields import RequestField
 
 {{#tornado}}
 import tornado.gen
@@ -169,6 +170,9 @@ class ApiClient(object):
             post_params = self.parameters_to_tuples(post_params,
                                                     collection_formats)
             post_params.extend(self.files_parameters(files))
+            if header_params['Content-Type'].startswith("multipart"):
+                post_params = self.parameters_to_multipart(post_params,
+                                                          (dict) )
 
         # body
         if body:
@@ -243,6 +247,26 @@ class ApiClient(object):
                                       response_data.getheaders()))
 {{/tornado}}
 
+    def parameters_to_multipart(self, params, collection_types):
+        """Get parameters as list of tuples, formatting as json if value is collection_types
+
+        :param params: Parameters as list of two-tuples
+        :param dict collection_types: Parameter collection types
+        :return: Parameters as list of tuple or urllib3.fields.RequestField
+        """
+        new_params = []
+        if collection_types is None:
+            collection_types = (dict)
+        for k, v in params.items() if isinstance(params, dict) else params:  # noqa: E501
+            if isinstance(v, collection_types): # v is instance of collection_type, formatting as application/json
+                 v = json.dumps(v, ensure_ascii=False).encode("utf-8")
+                 field = RequestField(k, v)
+                 field.make_multipart(content_type="application/json; charset=utf-8")
+                 new_params.append(field)
+            else:
+                 new_params.append((k, v))
+        return new_params
+
     @classmethod
     def sanitize_for_serialization(cls, obj):
         """Builds a JSON POST object.
diff --git a/samples/client/petstore/python/petstore_api/api_client.py b/samples/client/petstore/python/petstore_api/api_client.py
index 11aa326965b..1d3ba2417c5 100644
--- a/samples/client/petstore/python/petstore_api/api_client.py
+++ b/samples/client/petstore/python/petstore_api/api_client.py
@@ -18,6 +18,7 @@ import os
 import re
 import typing
 from urllib.parse import quote
+from urllib3.fields import RequestField
 
 
 from petstore_api import rest
@@ -171,6 +172,9 @@ class ApiClient(object):
             post_params = self.parameters_to_tuples(post_params,
                                                     collection_formats)
             post_params.extend(self.files_parameters(files))
+            if header_params['Content-Type'].startswith("multipart"):
+                post_params = self.parameters_to_multipart(post_params,
+                                                          (dict) )
 
         # body
         if body:
@@ -231,6 +235,26 @@ class ApiClient(object):
             return (return_data, response_data.status,
                     response_data.getheaders())
 
+    def parameters_to_multipart(self, params, collection_types):
+        """Get parameters as list of tuples, formatting as json if value is collection_types
+
+        :param params: Parameters as list of two-tuples
+        :param dict collection_types: Parameter collection types
+        :return: Parameters as list of tuple or urllib3.fields.RequestField
+        """
+        new_params = []
+        if collection_types is None:
+            collection_types = (dict)
+        for k, v in params.items() if isinstance(params, dict) else params:  # noqa: E501
+            if isinstance(v, collection_types): # v is instance of collection_type, formatting as application/json
+                 v = json.dumps(v, ensure_ascii=False).encode("utf-8")
+                 field = RequestField(k, v)
+                 field.make_multipart(content_type="application/json; charset=utf-8")
+                 new_params.append(field)
+            else:
+                 new_params.append((k, v))
+        return new_params
+
     @classmethod
     def sanitize_for_serialization(cls, obj):
         """Builds a JSON POST object.
diff --git a/samples/openapi3/client/extensions/x-auth-id-alias/python/x_auth_id_alias/api_client.py b/samples/openapi3/client/extensions/x-auth-id-alias/python/x_auth_id_alias/api_client.py
index f99907a757f..d3e98a2a55b 100644
--- a/samples/openapi3/client/extensions/x-auth-id-alias/python/x_auth_id_alias/api_client.py
+++ b/samples/openapi3/client/extensions/x-auth-id-alias/python/x_auth_id_alias/api_client.py
@@ -18,6 +18,7 @@ import os
 import re
 import typing
 from urllib.parse import quote
+from urllib3.fields import RequestField
 
 
 from x_auth_id_alias import rest
@@ -171,6 +172,9 @@ class ApiClient(object):
             post_params = self.parameters_to_tuples(post_params,
                                                     collection_formats)
             post_params.extend(self.files_parameters(files))
+            if header_params['Content-Type'].startswith("multipart"):
+                post_params = self.parameters_to_multipart(post_params,
+                                                          (dict) )
 
         # body
         if body:
@@ -231,6 +235,26 @@ class ApiClient(object):
             return (return_data, response_data.status,
                     response_data.getheaders())
 
+    def parameters_to_multipart(self, params, collection_types):
+        """Get parameters as list of tuples, formatting as json if value is collection_types
+
+        :param params: Parameters as list of two-tuples
+        :param dict collection_types: Parameter collection types
+        :return: Parameters as list of tuple or urllib3.fields.RequestField
+        """
+        new_params = []
+        if collection_types is None:
+            collection_types = (dict)
+        for k, v in params.items() if isinstance(params, dict) else params:  # noqa: E501
+            if isinstance(v, collection_types): # v is instance of collection_type, formatting as application/json
+                 v = json.dumps(v, ensure_ascii=False).encode("utf-8")
+                 field = RequestField(k, v)
+                 field.make_multipart(content_type="application/json; charset=utf-8")
+                 new_params.append(field)
+            else:
+                 new_params.append((k, v))
+        return new_params
+
     @classmethod
     def sanitize_for_serialization(cls, obj):
         """Builds a JSON POST object.
diff --git a/samples/openapi3/client/features/dynamic-servers/python/dynamic_servers/api_client.py b/samples/openapi3/client/features/dynamic-servers/python/dynamic_servers/api_client.py
index 6e7150a6d1a..4277fa448dd 100644
--- a/samples/openapi3/client/features/dynamic-servers/python/dynamic_servers/api_client.py
+++ b/samples/openapi3/client/features/dynamic-servers/python/dynamic_servers/api_client.py
@@ -18,6 +18,7 @@ import os
 import re
 import typing
 from urllib.parse import quote
+from urllib3.fields import RequestField
 
 
 from dynamic_servers import rest
@@ -171,6 +172,9 @@ class ApiClient(object):
             post_params = self.parameters_to_tuples(post_params,
                                                     collection_formats)
             post_params.extend(self.files_parameters(files))
+            if header_params['Content-Type'].startswith("multipart"):
+                post_params = self.parameters_to_multipart(post_params,
+                                                          (dict) )
 
         # body
         if body:
@@ -231,6 +235,26 @@ class ApiClient(object):
             return (return_data, response_data.status,
                     response_data.getheaders())
 
+    def parameters_to_multipart(self, params, collection_types):
+        """Get parameters as list of tuples, formatting as json if value is collection_types
+
+        :param params: Parameters as list of two-tuples
+        :param dict collection_types: Parameter collection types
+        :return: Parameters as list of tuple or urllib3.fields.RequestField
+        """
+        new_params = []
+        if collection_types is None:
+            collection_types = (dict)
+        for k, v in params.items() if isinstance(params, dict) else params:  # noqa: E501
+            if isinstance(v, collection_types): # v is instance of collection_type, formatting as application/json
+                 v = json.dumps(v, ensure_ascii=False).encode("utf-8")
+                 field = RequestField(k, v)
+                 field.make_multipart(content_type="application/json; charset=utf-8")
+                 new_params.append(field)
+            else:
+                 new_params.append((k, v))
+        return new_params
+
     @classmethod
     def sanitize_for_serialization(cls, obj):
         """Builds a JSON POST object.
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 ac0fb625b16..73d7c9adeeb 100644
--- a/samples/openapi3/client/petstore/python/petstore_api/api_client.py
+++ b/samples/openapi3/client/petstore/python/petstore_api/api_client.py
@@ -18,6 +18,7 @@ import os
 import re
 import typing
 from urllib.parse import quote
+from urllib3.fields import RequestField
 
 
 from petstore_api import rest
@@ -171,6 +172,9 @@ class ApiClient(object):
             post_params = self.parameters_to_tuples(post_params,
                                                     collection_formats)
             post_params.extend(self.files_parameters(files))
+            if header_params['Content-Type'].startswith("multipart"):
+                post_params = self.parameters_to_multipart(post_params,
+                                                          (dict) )
 
         # body
         if body:
@@ -231,6 +235,26 @@ class ApiClient(object):
             return (return_data, response_data.status,
                     response_data.getheaders())
 
+    def parameters_to_multipart(self, params, collection_types):
+        """Get parameters as list of tuples, formatting as json if value is collection_types
+
+        :param params: Parameters as list of two-tuples
+        :param dict collection_types: Parameter collection types
+        :return: Parameters as list of tuple or urllib3.fields.RequestField
+        """
+        new_params = []
+        if collection_types is None:
+            collection_types = (dict)
+        for k, v in params.items() if isinstance(params, dict) else params:  # noqa: E501
+            if isinstance(v, collection_types): # v is instance of collection_type, formatting as application/json
+                 v = json.dumps(v, ensure_ascii=False).encode("utf-8")
+                 field = RequestField(k, v)
+                 field.make_multipart(content_type="application/json; charset=utf-8")
+                 new_params.append(field)
+            else:
+                 new_params.append((k, v))
+        return new_params
+
     @classmethod
     def sanitize_for_serialization(cls, obj):
         """Builds a JSON POST object.