What is the ruling on the commission taken by an employee in a commercial company from buyers in exchange for them getting a good price?

If the agreement with the buyer is outside official working hours, then there is no harm in brokerage, which is the mediation between the seller and the buyer to complete a sale. However, if the agreement is during official working hours, then permission from the employer is necessary, because the employee's time belongs to the employer. If you are the company's sales manager, then you are not permitted to do this even outside working hours, because it contradicts working for the benefit of the company.