Force Majeure
Lex mercatoria:
an event of Force Majeure (FM) must have been extraordinary and unforeseeable when the obligation was contracted (e.g. date of signature of the agreement). Epidemics, riots, wars, air crashes fit the definition. It is less clear if crimes and other rare but non-catastrophic occurrences, such as a court decision that departs from established legal principles, amount or not to FM
FM must be unavoidable: You will not be excused if You could have avoided the event by taking reasonable precautions
FM work for both parties to the contracts, not only one
FM is a shield, not a sword: it will excuse You from failure to perform your obligations, e.g. to make payments or to provide services, but will not give You a cause of action in court
often you can rely on FM even where Your contract does not include a FM clause. This is so because the law of your contract is likely to assume that both parties to the contract implied that, in case of unforeseeable and extraordinary events, none of them will be liable for failure to perform what promised
learn more: https://www.trans-lex.org/944000/_/force-majeure/
Czech law:
According to Article 2913, comma 2, of the Czech Civil Code (Act No 89/2012 Collection of Laws) an ‘unsurmountable, unforeseeable event’ will excuse a party to a contract from the obligation to pay or otherwise compensate damages to the other party