Is the monthly fee, which includes interest, to a company that leases the necessary equipment for opening businesses, considered usury, knowing that banks contribute to the capital of these companies and there is no Islamic bank in Tunisia?

The service provided by the company is either leasing (ijarah (definition)) or selling. If it is a lease of equipment and devices for a monthly fee, it is permissible as long as it does not include consumables. If it is an installment sale with an increase in price, it is permissible, provided that the commodity is owned by the seller and is in his possession. However, if the company does not own the commodity and pays its value as a loan to the buyer with an increase, this is prohibited usury (riba), and it is not permissible to work for this company in this field. Accordingly, a person who works in prohibited activities while not being compelled to do so is not considered pleasing in his religion, based on the saying of the Prophet (peace be upon him): "If someone whose religion and character you are pleased with comes to you, then marry him."