Disable the acceleration of my touchpad (libinput)

I'm using libinput, feeding my touchpad. I would like to use it without acceleration, exactly like my mouse (by default in Manjaro). So I tried to modify my /usr/share/X11/xorg.conf.d/40-libinput.conf file:

    InputClass section
Identifier "touchpad libinput catchall"
MatchIsTouchpad "on"
MatchDevicePath "/ dev / input / event *"
Driver "libinput"
"ProfileAcceleration" option "-1"
"AccelerationScheme" option "none"
Option "AccelSpeed" "-1"
EndSection

But these 3 options make my pointer very slow and do not turn off the acceleration. (according to https://unix.stackexchange.com/questions/392749/mouse-touchpad-acceleration-disabling-not-working and http://www.webupd8.org/2016/08/how-to-completely-disable – mouse.html)