Expert article • Obligatory law • Reading time: ~6 min
Principles of the law of obligations in practice: conscientiousness, fairness and the limits of contractual freedom
At the heart of every contractual relationship are the fundamental principles of the law of obligations — freedom of contract, equality of parties, conscientiousness and fairness, prohibition of abuse of rights and the duty of cooperation and careful conduct. These principles are not just legal phrases, but concrete standards of conduct that shape legal transactions and protect trust between participants.
1) Freedom of contract and its limits
According to Art. 2 of the ZOO, parties may regulate their obligatory relationships as they wish, but may not act contrary to the Constitution, mandatory regulations and the morality of society. In practice, this means that creative solutions and ‘custom’ clauses are permitted — as long as they do not endanger public order, equal treatment and a minimum of fairness in legal transactions (Art. 3 and 4).
2) Good faith and honesty: a standard that holds contracts together
The principle of good faith and honesty (Art. 4) binds the parties both when concluding and fulfilling a contract. No one should assert a right contrary to the purpose for which it was granted (prohibition of abuse of rights — Art. 6), nor make it difficult for the other party to fulfill its obligation (Art. 10, paragraph 3).
Case law: when ‘confirmation of receipt’ is not what it seems
The Commercial Court in Rijeka (P-247/2019-9) ruled on an attempt to collect payment for products from an elementary school. A company representative came to the school unannounced, left a ‘free sample copy’ of a printed directory and gave a form for signature, explaining that it was only a confirmation of receipt. Later, the company tried to present this document as a sales contract and charge for the product. The court concluded that such conduct was contrary to the principle of conscientiousness and honesty and the moral criteria required by mandatory law — and ruled in favor of the school.
3) Duty of cooperation and due care of a good professional
Art. 5 establishes a duty of cooperation for the proper fulfillment of obligations; Art. 10 requires the care of a good businessman (or a good host), and for professionals, ‘increased care’ according to the rules of the profession. Establishing clear communication, timely delivery of information and avoiding ambiguous actions minimize the risk of disputes.
4) Equal value of services and dispositive nature of rules
In the case of payment contracts, the principle of equal value of mutual services (Art. 7) is used. Many provisions of the ZOO are dispositive (Art. 11) — parties can adapt them, but not bypass mandatory regulations or morality. In relations between traders, agreed commercial customs and developed practices play an important role (Art. 12).
Practical guidelines
- The titles of documents must correspond to the content. Do not sign ‘confirmations’ that contain an obligation to purchase.
- Include clauses on purpose and transparency — e.g., explicitly exclude payment if it is a demonstration.
- For professionals: document all actions and decisions (the attention of a good professional).
- If you are suspicious — seek legal advice before signing.
