IBM Watson Speech to Text in Python gives 404 when using model parameter

The model should be passed as part of the recognize method

speech_recognition_results = speech_to_text.recognize(
        audio=audio_file,
        content_type='audio/mp3',
        word_alternatives_threshold=0.9,
        model='fr-FR_BroadbandModel'
    ).get_result()

Pasting the complete code that worked me for your reference

import json
from os.path import join, dirname
from ibm_watson import SpeechToTextV1
from ibm_cloud_sdk_core.authenticators import IAMAuthenticator

authenticator = IAMAuthenticator('<API_KEY>')
speech_to_text = SpeechToTextV1(
    authenticator=authenticator
)

speech_to_text.set_service_url('<URL>')

with open(join(dirname(__file__), './.', 'audio-file2.mp3'),
               'rb') as audio_file:
    speech_recognition_results = speech_to_text.recognize(
        audio=audio_file,
        content_type='audio/mp3',
        word_alternatives_threshold=0.9,
        model='fr-FR_BroadbandModel'
    ).get_result()
print(json.dumps(speech_recognition_results, indent=2))