Different French keyboard layout There are 2 Mac French keyboard layouts.

The standard one :


And another one :


I would like to use the second kind of keyboard on Windows. Meaning now if I plug it, the keys don't match, what gets sent to Windows is not what appears on the keyboard. With the first type of keyboard I could install a "French" "Mac" keyboard layout, that worked well. Thus I am looking for the relevant keyboard layout to install on Windows.

Where can I find it, and what is it called ?

The reason I am saying that the second keyboard is "standard", is because on a Mac, if one takes a US keyboard (with the key shapes like the second picture), and selects "French" as input language, then the mapping is exactly the same as the second picture.
You would have to search online for a Windows keyboard called French (Apple).  I don't know if one exists.  And it would be for your top picture.  Your bottom picture looks non-standard and non-Apple.  All European keyboards should be ISO and have the extra key next to the shift in the bottom row.

You might need to make a custom Windows keyboard with the MKLC app.

https://www.microsoft.com/en-us/download/details.aspx?id=22339

You should probably really ask in a forum for Windows instead of Mac.