In the normal cases where someone pays the other some money or delivers him a property for payment of its debt, it is assumed that the payer is going to discharge his debt. Though, there are some cases where the payment is not made for discharging a debt. Thus, under such circumstances, the payer has the right of restitution of the money or property paid. This case is dealt with in both French and English legal systems. Unlike the French civil law, the Iranian civil code, without allocating a quasi-contractual title for such erroneous payment, has chosen one of the dual traditional categories of obligations and titled it "obligations which derive out of a non-contractual relationship".
As it will be shown, this type of payments is done due to a mistake that differs from ignorance. For establishing restitution of an erroneous payment, certain conditions should be respected. The aforesaid payment creates certain obligations for the receiving party, namely, restitution of the property and reimbursement of benefits received. In some instances after the restitution of the property, the recovery of expenses incurred by the receiving party shall be also paid.
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