From ArchWiki

Got problems with your Apple Keyboard, the aluminium version?

[edit] F1-F4 buttons doesn't work

If your problem is that the F1-F4-buttons doesn't work, do this as root:

echo 2 > /sys/module/hid/parameters/pb_fnmode

and place it in /etc/rc.local to make the setting permanent.

[edit] < and > have changed place with § and ½

If the < and > are switched with the § and ½ keys, do the following:

setxkbmap -option apple:badmap

Place that in ~/.bash_profile, or if you use KDE:

Go to the "Control Center" -> "Regional & Accessibility" -> "Keyboard Layout" and press the "Xkb Options" tab. Scroll down and check the "apple" and "Swap keycodes of..." checkboxes. Click on "Apply".