Here is the Curl:
curl https://api-inference.huggingface.co/models/speechbrain/asr-wav2vec2-commonvoice-fr \
-X POST \
--data-binary '@sample1.flac' \
-H "Authorization: Bearer {API_TOKEN}"
Their is not particular multipart loading requirement from which i understand from the description, and i manage to make it work easily with the web browser or Postman: