Tenancy law: What to do in case of landlord's office use?

Questioner

My daughter rents a house from a private individual with a rental contract. Now the landlord wants to use a room as an office space. He will be there during the day. There are no rooms that can be closed off. She is not present there during the day. Can the landlord just do this? In my opinion, this is a violation of my daughter's privacy. How can we prevent this? Without this having any negative consequences for her, for example by terminating the lease on the part of the landlord.

Lawyer

Your daughter rents a house and all the rooms belong to it. She does not have to tolerate the landlord using a room for herself. However, if she agrees, she can negotiate a price reduction on the rent. What kind of contract does she have?

Questioner

At the moment a one year contract until June 30th then for an indefinite period. She also gave approval that he could make an office space there provided she got a lock on her room and shower. This has not happened yet, but it seems that there will be a lock for the room now because the gentleman wants to be able to lock his own room.

Lawyer

Your daughter is entitled to a price reduction, but I would wait until the contract has been converted.

Questioner

Okay, and what rights does she and the tenant have?