Is it permissible to take a sum of money from a person in exchange for writing a deed for him of the same value, on condition that this person takes a commission of 30 dinars for every 1000 dinars?

The transaction mentioned is forbidden Riba (usury), because it involves exchanging money for money of the same currency without fulfilling the two conditions of equivalence and immediate possession. Your payment of one thousand thirty dinars for one thousand negates equivalence, and the non-receipt of the money at the contract session negates immediate possession. This is what the Prophetic Hadiths forbade, as they stipulated equivalence and immediate possession when exchanging usurious commodities of the same type. Furthermore, borrowing money from your friend with the condition of an increase is unanimously considered forbidden Riba.