Article 28 of Private Sector Labour Law

The employment contract shall be evidenced in writing and shall specify, in particular, the date of conclusion of the contract, its effective date, the amount of the wage, the term of the contract if it is for a fixed term, and the nature of the work. It shall be drawn up in three copies, one given to each party and the third deposited with the competent authority at the Ministry. If the employment contract is not evidenced in a written instrument, the contract shall be deemed to exist, and the worker may in that case prove his right by all means of proof. Whether the employment contract is for a fixed or indefinite term, the worker's wage may not be reduced during the period in which the contract is in force. Any agreement preceding or subsequent to the contract taking effect that contravenes this shall be absolutely null and void as a matter of public order. The employer may also not assign the worker work inconsistent with the nature of the work specified in the contract or unsuitable for the worker's qualifications and experience on the basis of which he was contracted.