Answer
Wa `alaykum as-Salamu wa rahmatullahi wa barakatuh.
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
The lessee can use the rented property in the way he wishes as long as he does not hurt the asset, i.e., the apartment.
In his response to your question, Prof. Dr. Monzer Kahf, Professor of Islamic Finance and Economics at Qatar Faculty of Islamic Studies, states:
The lessee can do whatever he likes to do with the usufruct he owns. He can even sub-lease the property to somebody else provided that it does not hurt the asset (apartment).
You have no right to restrict the lessee except in case of violating the law or harming the rented asset.
Allah Almighty knows best.
Editor’s note: This fatwa is from Ask the Scholar’s archive and was originally published at an earlier date.