The choice of applicable law may be expressly mentioned in the contract, but it may also be a tacit reference, provided that it clearly emerges from the provisions of the contract or from the circumstances of the case.
This will is manifested in express terms, where the contracting parties have taken care to insert a special clause designating the law which is to govern the contract.
That clause may, from the outset, be incorporated in the employment contract or included in a later addendum.
The parties may designate the law applicable to their entire contract or to only a part of it.
Their choice may also involve several laws applicable to the employment contract.
Similarly, the contracting parties may subsequently alter their choice. Where the new will of the parties is established, it replaces the previous will.