Oh, I see. So the EU is just trying to outlaw the practice of marking the price up for a day so they can then mark it "50% off" the following day. Good for the EU. That practice stinks.
You can reduce it all you want. What you can't do is say "this house is 50% off" because you doubled the asking price for half an hour the previous week and then dropped it again.
It's a false advertising issue, not price controls.