This review contains two commentaries to the rulings of the Polish Supreme Court dealing with a contractual penalty stipulated in the contract and a applicable law to employment contract. The first commentary concerns a ruling issued on the basis of a legal question regarding doubts as to whether the general inadmissibility of stipulating a contractual penalty in the event of failure to perform or improper performance of pecuniary obligation also extends to the case of a contractual penalty reserved in a contract concluded under public procurement law in the event of non-payment by the general contractor of remuneration to its subcontractors. The Supreme Court adopted a resolution, the content of which should not raise any reservations regarding the issue of contracts concluded under the public procurement law. However, the question remains whether the same provisions are permissible in general contractor agreements concluded outside this particular legal regime. The second commentary aims to comment a ruling concerning the law applicable to individual employment contracts. The question referred in the present case arises in the context of a dispute between an international lorry driver domiciled in Poland and a Polish company that had employed this driver, concerning remuneration for overtime work. In the judgement I PK 267/18, Polish Supreme Court has assumed that Polish law applied to the case as a whole, although the employee had been performing the essential part of his duties abroad, delivering goods from Italy to customers in various European countries. Meanwhile, Article 8(2) of Rome I Regulation provides that the individual employment contract shall be governed by the law of the country in which or, failing that, from which the employee habitually carries out his work in performance of the contract. Furthermore, the Court of Justice of the European Union, in the judgement C-29/10 (Heiko Koelzsch v. État du Grand-Duché de Luxembourg), based on the similar case and Article 6(2)(a) of the Convention on the law applicable to contractual obligations (which was less precise in this regard), assumed that in a situation in which an employee carries out his activities in more than one Contracting State, the country in which the employee habitually carries out his work in performance of the contract, within the meaning of that provision, is that in which or from which, in the light of all the factors which characterise that activity, the employee performs the more significant part of his obligations towards his employer.