Ruling on renting out a hall to someone who will hold a mixed party there
Question

                What is the ruling on renting out halls when some of the parties will not follow the rulings of sharee’ah?.
Praise be to Allah.It is not permissible to 
    rent out halls to those who will hold parties that involve sinful things, 
    such as mixing between men and women, or haraam music and other sins, 
    because Allaah says (interpretation of the meaning): 
“Help you one another in 
    Al‑Birr and At‑Taqwa (virtue, righteousness and piety); but do not help one 
    another in sin and transgression. And fear Allaah. Verily, Allaah is Severe 
    in punishment”
[al-Maa’idah 5:2]
The scholars (may Allaah 
    have mercy on them) stated that it is haraam to rent out a house to one who 
    is going to use it in disobedience of Allaah. 
It says in Mataalib Ooli 
    al-Nuha (3/607): It is not valid to rent out a house to be used as a 
    church, synagogue, monastic cell, house of fire for Magian worship, for 
    selling alcohol or gambling, because that is helping in sin and Allaah says 
    “do not help one another in sin and transgression”. (And it is not 
    valid) to rent the house out for music or anything else that the Lawgiver 
    has forbidden. End quote. 
It says in al-Mawsoo’ah 
    al-Fiqhiyyah (8/228): Because the purpose of the rental contract is to 
    sell use of the house for a specific period, the same stipulation is made 
    concerning its use as is made in a contract of sale, which is that there 
    should be no shar’i impediment to the use made of it such as it being 
    haraam, as in the case of alcohol, musical instruments and pork. According 
    to the majority of fuqaha’ it is not permissible to rent out a house for 
    purposes that are not acceptable according to sharee’ah, such as if the 
    renter is going to use it as a place for drinking alcohol or gambling, or he 
    is going to use it as a church or place of idol-worship. In that case it is 
    haraam to take the rent just as it is haraam to give it, because that is 
    helping in sin. End quote. 
And Allaah knows best.