What is the ruling of Islamic law on taking a commission for advertising a product, knowing that this commission does not increase the price of the product and the company's aim is to increase sales?

The commission specified by the company is permissible, even if there is some ambiguity in it, because it falls under the category of a fixed remuneration (Ja'l), in which ambiguity does not cause harm if it does not prevent delivery, according to some jurists. However, one must beware of promoting a product falsely to obtain a larger percentage, in order to avoid prohibited deception.