When a case comes before a court and all the main features of the case are local, the court will apply the lex fori, the prevailing municipal law, to decide the case. But if there are "foreign" elements to the case, the forum court may be obliged under the conflict of laws system to consider:
whether the forum court has jurisdiction to hear the case ;
it must then characterise the issues, i.e. allocate the factual basis of the case to its relevant legal classes; and
then apply the choice of law rules to decide which law is to be applied to each class.
The lex loci contractus is one of the possible choice of law rules applied to cases testing the validity of a contract. For example, suppose that a person domiciled in Canada and a person habitually resident in France, make a contract by e-mail. They agree to meet in New York State to record a CD of hip hop music. The possibly relevant choice of law rules would be:
the lex domicilii and law of habitual residence to determine whether the parties had the capacity to enter into the contract;
the lex loci contractus which could be difficult to establish since neither party left his own jurisdiction ;
the lex loci solutionis might be the most relevant since New York is the most closely connected to the substance of the obligations assumed;
the lex fori which might have public policy issues if, say, one of the parties was an infant.
Implications
The provisions of this legal concept can be construed to confirm the following:
If a contract is valid where it was consummated, it is valid everywhere ;
If a contract is void where it was consummated, it is void everywhere ;
An exception in comity exists: The agreement will not be held valid in the forum country if it violates the law of the forum country, or if it violates the law of nature, or if it violates the Law of God;
A contract may be deemed valid in lex loci contractus, but if it is a revenue law of that state it will not be enforced in the forum state.
If a contract is consummated in one state but its content specifies that it is to be carried out in another state, two loci are thus generated: locus celebrate contractus and locus solutionis. The laws of the locus celebrate contractus state will govern all matters concerning the mode of constructing the contract, the meaning of each factor therein, the nature of the contract, and its validity. The laws of the locus solutionis state will apply to the performance or execution of the contract.
Determination at law
Sometimes, the locus contractus is difficult to determine, for example if the contract was signed at sea or on a moving train or if the details of the contract signing were not well documented. If a court is called upon to determine the applicable state, it may use any or all of the following factors:
The residence or main domicile of the signatory parties;
The main place of business of the signatory parties;
