Is purchasing an apartment for someone residing in Italy for 50,0 dirhams to avoid an interest-based loan, in exchange for renting it for 450 dirhams while the normal rental price is 1200 dirhams, considered a legitimate transaction in Islamic law?

Every loan that draws a benefit is usury (riba), such as the borrower allowing the lender to live in his house, or renting it to him for less than the market rent. This is forbidden in Islamic law. The questioner must repent, annul the forbidden contract, calculate the market rent for the past period, and pay the difference to the lender because it is in exchange for the loan.