See this thread How to send JSON as part of multipart POST-request
Do not set the Content-type header yourself, leave that to pyrequests to generate
def send_request():
payload = {"param_1": "value_1", "param_2": "value_2"}
files = {
'json': (None, json.dumps(payload), 'application/json'),
'file': (os.path.basename(file), open(file, 'rb'), 'application/octet-stream')
}
r = requests.post(url, files=files)
print(r.content)