Is the mediation between a financier and a contractor, whereby the mediator takes money from the financier and gives it to the contractor to obtain a known monthly profit from it (such as 5,0 for every share of 100,0), and then divides this profit with the financier, with the financier's knowledge that the mediator is profiting from these funds, permissible in Islamic law?

The aforementioned transaction is impermissible, whether it be mudarabah (profit-sharing) or wakalah (agency). In mudarabah, it is stipulated that the share of profit for both parties must be specified, and it is not permissible for it to be a fixed sum or a known percentage of the capital. In wakalah for a fee, the fee must be specified. Neither the mudarib nor the agent guarantees the capital unless there is transgression or negligence.