A man has built a building whose ground floor is suitable for stalls, but whose upperfloors are not. Is it permissible to rent the upper floors for use as restaurants?
Keeping in mind that prohibited and immoral acts may be committed therein?

It is established in Islamic law that anything is permissible provided it is not explicitly declared prohibited. Based on this, if something can be used for either purpose (lawful and prohibited), it is permissible to dispose of it as one wishes, e.g., by renting, selling, etc… . The responsibility of using it appropriately lies upon the user. If he uses it in permissible ways, then it is permissible. And if he uses it in impermissible ways, it is impermissible.

The above answers the question.