As part of our cooperation with the Poznań branch of the Polish Association of Developers (PZF), we have had another opportunity to conduct training for its members: developers investing in Poznań and the neighbouring areas. This time, we discussed contractual penalties, one of the most common of the so-called additional contractual reservations. During the 3-hour training we explained the potential benefits of contractual penalties for the investor, and the potential risks for the contractor. We would like to thank everyone for active participation and lively discussion.