Contract law governs virtually all aspects of the contract, including its validity, nature, content, nature and interpretation. However, on an exceptional basis, the contractual capacity of the parties and the formalities of execution are governed by the lex loci contractus, unless the contract concerns the property, the rule of law being applicable in the country where the property is located (lex situs or rei situae). It appears, however, that a contract that does not meet the form requirements of the lex loci contractus is formally valid if it corresponds to the form of contract law. In the case of a foreign exchange contract, a creditor is entitled to a full and complete benefit. There must be strict respect, in other words, 100% power. The principle of reciprocity recognizes that, in many contracts, the common intention of the parties, expressed or not, is that there should be an exchange of benefits. The creditor may therefore refuse any vaguely inappropriate benefit. The power of the component is not a power. If Iustus` error approach is applied in which there is an alleged agreement between the parties, the opponent is responsible for proof that its default is both essential and appropriate to be exempt from liability within the meaning of the apparent contract: lenders indicate full disclosure of all the terms of the loan in a credit agreement. The important credit terms included in the credit agreement include the annual interest rate, the application of interest on outstanding balances, all account-related fees, the duration of the loan, payment terms and possible consequences for late payments. Then there are the general clauses on variation, severance pay, full agreement, transfer, waiver, citandi and executandi (communications, address for Dies), applicable law and jurisdiction, alternative dispute resolution procedures, force majeure (against major and casus fortuitus), costs and confidentiality. There is some uncertainty as to what these requirements are. It is clear that the threat must be illegal or against bonos mores, and must have induced the contract.

According to some authorities, the induced party must have a justified fear of imminent or inevitable harm to itself, his property or his immediate family.