If you book in Berlin a minimum of 7 nights a week before your arrival, it will be 15% cheaper and if you book a minimum stay of 7 nights at Axel Two Barcelona, you'll get a 20% discount.

Don't be caught unprepared. Check out the conditions:
In Berlin possibility of modification or cancellation up to 7 days prior to the arrival date. Consult cancellation policy. Discount not applicable every day of the year and subject to availability of the hotel.