According to the Law on Privatization and the Law on Securities, share trading occurs on the Stock Exchange. In this case, you can only offer your shares for sale through a broker - brokers authorized to trade securities on the Stock Exchange, this way you are not scammed by a broker, just routed to offer your shares for legal sale.

If someone actually buys shares directly from a shareholder, most often this is achieved through bought votes in a shareholder's assembly and is part of documentation, which the "buyer" offers at signing power of attorney for voting in shareholders assembly.