All matters relative to the performance of a contract are governed by the law of the place where the contract is to be performed, i. e., the locus solutionis, while all matters relative to the consideration are governed by the law of the place where the consideration is to be given or paid, i. e. the locus considera-tionis.

In reality these two terms are interchangeable, as the performance on one side is the consideration for the performance on the other.