First of all, you will not regret it if you obtain written permission from your landlady before giving your flat the colourful finishing touches. She can refuse this without giving reasons, but once it has been granted, it cannot be revoked afterwards.
If you leave the flat again one day, your landlady can then demand that you restore the flat to its original condition – i.e. with white walls. If your walls still remain coloured after you move out, it is very likely that you will have to pay the costs of painters hired by the landlady. This is because painting the walls a different colour is a deviation from the condition when you took over the rented property. Accordingly, unless otherwise agreed, the landlady may require you to restore the original condition, i.e. to paint the wall white.
White walls therefore bring another advantage in addition to a bright and open effect – the good relationship between you and your landlady is preserved on this point.
If you have any questions regarding tenancy law, our lawyers will be happy to advise you.