How to make --model-file option work?

Unfortunately, if I attempt to use the --model-file option, for example

… --model-file /gguf/gemma-3-12b-it-Q4_K_M.gguf

it complains “error: a value is required for '–model , but none was supplied”

What can be done that the model file is being used instead of forced downloading the model from Huggingface? The latter is no option, as I intend to operate the translation servers in an airgapped internal network.