I am working with Film emulation.
In G'mic web page I read: " You can also download each color preset separately as its corresponding Hald-CLUT file (in .png format), to use it in other softwares that support this feature."
I can't found where get this files.
An other question: in Film emulation for slides we found "Generic kodachrome 64" and "Kodak kodachrome 64". What's difference between ? I confirm they don't give the same result !
Thanks for help.

To download the CLUT manually, just click on one of the image in the G'MIC film emulation page : http://gmic.eu/film_emulation , then you'll see a new link (on the image caption) : "Download CLUT" that points to the PNG file of the CLUT.
For the "Generic" vs "Kodak", we should let Pat David give an answer (I have no clues ).

OK it's work.

I see that it's a 512*512 picture, table for a RGB colour cube 64*64*64, so the colours are on 6 bits only. I think precision is enough for this kind of work, but each treatment needs interpolation with 8 neighbours to give a result on 8 bits. That increase processor's work, but the file is lighter !
Is Pat David on this forum ?

Yes, Pat is sometimes around.