I want to join an islamic society in europe. This society includes a mosque and dars.
The shura demands a membership fee. Is this halal?
If the situation is as described, there is nothing wrong with paying the fees demanded by the society and this is their right. If the one who pays the fee intends, in addition to benefiting from the activities, that what he pays is to support that society, then he will be rewarded for that intention, in sha Allah, especially since the Islamic societies and centres in Western countries are doing important work, such as teaching the Muslims about their religion and striving to spread Islam in those countries. They provide a good environment for the Muslims there, so supporting them financially and in other ways comes under the heading of calling people to Allah.
And Allah knows best.