apartment's owner asks for additional renting fee.

[christine_sg]

Me and my friend rent an apartment in Tampere. At first, we have lived there with 2 people. Then since september, one of my friend moved in. We have noticed that to the owners of the apartment through OVV (the house company). We paid additional price in water and electricity. But today we received a notification from OVV indicates that we need to pay additional 100 eur to the renting fee per month, starting right from November, because there is one more person living in the apartment.

Is that legal for the owner to ask for more renting fee without noticing with this reason? In my contract, there is no mention about the limitation in how many people could live there. As well as they are only allowed to add 5% of renting fee per time ( according to the contract). This time they ask for +18% of renting fee. That's too much! Even more, they ask for additional renting fee 2 months after my friends moved in. Ridiculous?

I want to ask for your kindness advice. What could we do in this situation?

Thank you for your time

[Rip]

Relevant law:
http://www.finlex.fi/fi/laki/kaannokset ... 950481.pdf

You know what kind of contract and apartment you have (is there a main tenant and sublease or what?), my understanding is that if you're within the legally protected sublease terms, the land lord has no right to ask extra rent.

Section 17
Assignment of a residential apartment to the use of another person

[...]
The tenant may also use the apartment as a joint home with his or her near relative or a near relative of his or her spouse or assign by sub-lease or otherwise no more than half of the residential apartment to another person’s use for residential purposes if this does not cause the lessor significant inconvenience or disturbance.

In any other event, the tenant shall not assign the apartment or any part of it to another person’s use without consent thereto expressed in the lease agreement or given separately by the lessor.