Massachusetts tends to be a very tenant friendly state. While many states allow the landlord to disagree with subletting, in this state a landlord cannot "unreasonably withhold" permission to do so. Your landlord may try to get around this by adding this fee to discourage subleasing.
I could not find any law in this state that prohibited a landlord from adding this fee; however, there may be specific restrictions depending on the district this rental is in.
Gail
