What is the ruling on those residing under the old rental system in Egypt, and what is the stratagem against the greed of landlords, and what is the ruling on one who signs a new contract and acts according to the provisions of the old law?

For the validity of a lease contract, the duration and the rent must be known. Any law that contradicts this is an injustice and an unlawful appropriation of people's wealth, and it is not permissible for a Muslim to act upon it or be content with it. The lessor and the lessee must adhere to the Sharia (definition) conditions for leasing, the most important of which are knowledge of the rent and the duration. It is stated in "Al-Mughni" and "Al-Mudawwana" that not specifying the duration invalidates the lease. Those who uphold the aforementioned law are sinful and must rectify their contracts. For the lessor, there is the rent of the like (اجرة المثل) for the enjoyment of the benefit in an invalid lease. If there is mutual consent on a known rent and a specified duration, there is no harm. As for estimating greed in house rents, it is appropriate that the rent should be the rent of the like (اجرة المثل) in terms of time and place.