Parties are free to regulate such clauses, except in cases concerning intentional fault, as defined below.
Under Polish law, liability is based on the concept of fault. As a general rule, if a party is not at fault, it is not liable for the non-performance or improper performance of a contract. Consequently, force majeure is, in essence, a set of circumstances for which a party cannot be at fault. At the same time, parties are free to regulate their liability under contract, except for liability for intentional acts (i.e. “intentional fault”).
Parties are free to provide for full liability for force majeure events in their contracts. They are also free to limit that liability, i.e. by listing force majeure events. However, parties cannot contractually change the established definition of force majeure. If a particular clause does not satisfy the abovementioned definition of force majeure (i.e. it includes events that are not external and unforeseeable, the effects of which cannot be avoided), it will be interpreted as an effective agreement of the parties as to circumstances for which they cannot be held liable.