The principle of the duty to fulfil obligations means that concluded agreements must be respected and fulfilled. Participants in an obligations relationship are required to fulfil their obligations and are liable for their performance.⁶⁵ This is a fundamental legal principle stating that contracts and agreements are binding on all parties that have voluntarily entered into them. This principle is crucial for maintaining legal stability, trust between parties in contractual relationships, and ensuring predictability and security in legal affairs. There are two exceptions to this principle: the occurrence of changed circumstances and force majeure.

Exercise:

1. Lease company, Ltd., and A concluded a contract under which the company granted A the use of a car, while A committed to paying a specified monthly amount. The contract stipulated that, despite the car being handed over to A, the company would remain its owner, and A would acquire ownership upon payment of the final monthly instalment.

• Can the contracting parties conclude a contract with the previously mentioned content, even though the OZ does not regulate leasing contracts? Explain your answer!
• Which rules will apply to the assessment of the legal relationship between the parties?

2. A and B concluded a lease agreement in January 2003, under which A leased a part of a structure (a roadside fence) to B, where B installed advertising displays. The contract was concluded for a period of ten years. The lessor committed not to enter into agreements with third parties for the lease of the land or structure that would allow the installation of advertising surfaces during the contract term. In the event of a breach of this obligation, the parties agreed on a contractual penalty amounting to three times the contractual value. A and B also agreed on the option of early termination, with a three-month notice period. A terminated the lease agreement by letter on 5 June 2007. In accordance with the contractual provisions, the notice period began on 1 July 2007 and ended at the end of September 2007. B claimed that on 19 November 2007, he noticed that his advertising panels had been removed and, in the following days, replaced with the advertising panels of a competing company. In his view, the termination of the lease agreement had no legal effect. According to B, the OZ does not provide for termination as a way of ending a long-term creditor-debtor relationship in contracts for which the duration is fixed. A argued that, although the law does not explicitly provide for this, it is not contrary to mandatory legal provisions for parties to allow the termination of a contractual relationship by notice even in agreements with a fixed duration.

Who is right? Explain your answer!

3. A, as the provider, and B, as the beneficiary, concluded a lifetime maintenance contract. B prevented A from fulfilling his obligations and unjustifiably refused their performance. Through a lawsuit, B requested the termination of the contract.

• Do you think B will succeed with the lawsuit for the termination of the lifetime maintenance contract?

• In contradiction with which principles would a position be, according to which a party, from whose personal sphere the reason for non-fulfilment of the contract or the intolerability of cohabitation arises, could always demand contract termination?

4. A submitted five illegally drafted payment orders to the bank under a false name, with a forged signature of the authorised person (B). Based on these orders, an amount of EUR 10,000 was transferred from B’s transaction account to an account that A had previously opened under a false name at another bank. A then withdrew the transferred amount from this account by presenting forged personal documents. A, by his appearance and demeanour, did not raise any suspicion. B filed a lawsuit against the banks, demanding compensation for the damage.

• By which legal standard will the bank’s diligence be assessed?
• Do you think the bank exercised sufficient diligence when allowing a person who identified themselves with personal documents as the account holder to dispose of the funds in that account?

5. A and B contractually agreed that A as the creditor may withdraw from the contract without granting an additional appropriate deadline if the debtor’s delay in performance lasts for eight days. Read the provisions of Article 104(1) and Articles 105(2) and (3) of the OZ and explain:

• Is such an agreement allowed?
• Which rule will be used?

6. George and Mark concluded a sales contract in which they set a limitation period of seven years and agreed that during Mark’s absence abroad from April to September 2016, the limitation period would not run.

• Can the contracting parties set a longer limitation period and agree that it will not run for a certain period? 
• What is the legal nature of the provision in Article 339 of the OZ?

7. George’s coat was stolen in the restaurant where he was dining after he had hung it on a coat rack near the entrance. He immediately informed the restaurant manager about the theft and requested compensation for the damage. The restaurant manager rejected George’s request, claiming that the restaurant is not responsible for guests’ personal belongings. He pointed to a notice on the wall near the coat rack stating that the restaurant informs guests that it is not liable for their lost personal belongings.

Is George entitled to compensation for the damage?

8. Provision of Article 8(2) of the OZ shows that a disproportion in the value of performances is not always sanctioned, but only in cases where the law specifies that a violation of the principle of equal value of performances has legal consequences.⁶⁶

Find at least two examples in the OZ where the law prescribes legal consequences for a violation of the principle of equal value of performances!