Guixsd adds 2 hours to a BIOS time

[Adam Mazurkiewicz]

I live in Poland and I set time in config.scm in this way:
(...)
(operating-system
  (host-name "s")
  (timezone "Europe/Warsaw")
  (locale "en_US.utf8")

  (keyboard-layout (keyboard-layout "pl"))
(...)
Then I changed Warsaw to Paris because both have the same timezone and
DST (Daylight Saving Time).

In both cases, Warsaw and Paris, Guixsd added two hours to the time
that was set in computer BIOS. So the 'date' command in the terminal
gave wrong time, to hours later.

Setting the BIOS time to a two hours earlier time is not a good
solution, I think. What to do to fix this 2 hours offset?