Article 117 of Private Sector Labour Law

A collective employment contract may be concluded at the establishment, industry, or national level. If a collective employment contract is concluded at the industry level, it must be concluded on behalf of the workers by the federation of industry trade unions, and if it is concluded at the national level, it must be concluded by the General Federation of Workers. A contract concluded at the industry level shall be considered an amendment to the contract concluded at the establishment level, and a contract concluded at the national level shall be considered an amendment to either of the other two contracts, within the limits of the common provisions contained in them.