Can't find a way to preseed keyboard layout for all d-i questions

[Yvan Masson <yvan@masson-informatique.fr>]

Hi,

I am automating Buster installations with a preseed file. To do this, I 
boot the installer successfully with parameters `auto=true 
url=tftp://my_server domain=mydomain`.

However, before loading preseed.cfg, installer asks for computer name: I 
would like this question to be asked in French and more importantly to 
have the keyboard layout configured in French.

I have tried many boot parameters (layout=fr, layout=fr(latin9), 
language=fr, language=fr_FR.UTF-8…) but could not find anything working.

After answering this question, preseed.cfg is loaded so language and 
keyboard layout are properly applied.

Any idea?

Thanks,
Yvan