According to Swiss law, an individual employment contract is a contract whereby the employee undertakes to work in the employer’s service for either a fixed or an indefinite period of time and the employer undertakes to pay him a salary based either on time periods (time wage), or on the work performed (piecework wage).
Such a contract may be concluded in writing, verbally or even tacitly (i.e. inferred from the parties’ conduct), although some employment contracts (apprenticeship or travelling salesman contracts) must be in writing to be valid.
Based on the principle of freedom of contracts and within the limits of the law, the content of an individual contract of work is basically freely agreed between the parties. Nevertheless the Swiss Code of Obligations sets forth some mandatory statutory provisions that can be grouped into two categories: those that cannot be altered to the detriment of either party, and those that cannot be altered to the detriment of the employee.
Terms of a contract cannot be changed unilaterally but can be altered at any time by mutual consent. Nevertheless, one party may terminate the employment contract, subject to the notice period, and offer to the other party to conclude a new one with modified provisions.