Constitutional Court: Requirement for Joint Participation of Principal and Subcontractor Employers in Mediation on Reinstatement Violates the Principle of Proportionality

The Adana 6th Labour Court applied to the Constitutional Court, requesting the annulment of Article 3, paragraph fifteen, of the Labour Courts Law No. 7036 dated October 12, 2017, which provides that:

"In cases where a principal–subcontractor relationship exists, if an application for mediation is filed for reinstatement, both employers must participate in the mediation sessions together, and their declarations of intent must be consistent for a settlement to be reached."

The Constitutional Court examined the allegation of unconstitutionality regarding the contested provision. Upon evaluating the rule within the framework of the three sub-principles of the principle of proportionality — suitability, necessity, and proportionality — guaranteed under Article 13 of the Constitution, the Court concluded that the provision violated the principle of proportionality in terms of the sub-principle of proportionality itself.

In its reasoning, the Court stated that the provision imposed on the employee the obligation of investigating the existence of a principal–subcontractor relationship and conducting the mediation process jointly against both employers, thereby placing a heavy burden on the employee.

The Court emphasized that in most cases, it is not possible for the employee to be aware of the existence of a principal–subcontractor relationship; therefore, conditioning the validity of a mediation application upon the joint participation of both employers constitutes a violation of the principle of proportionality.

Accordingly, in its decision published in the Official Gazette dated October 17, 2025, the Constitutional Court ruled that paragraph fifteen of Article 3 of the Labour Courts Law No. 7036, which required both the principal and subcontractor employers to jointly participate in mediation sessions for a settlement to be valid, is unconstitutional, and annulled the provision.

Conclusion

This ruling once again highlights the importance of principal and subcontractor employers structuring their legal relationships in a transparent and well-documented manner. In particular, subcontracting agreements should be drafted in a way that clearly indicates under whose management and supervision the employees actually work, which is crucial to preventing potential disputes in the future.

Furthermore, strengthening communication and cooperation mechanisms between employers regarding participation in mediation processes will contribute both to shortening judicial proceedings and to fostering a culture of reconciliation.

You can access the related decision here. (In Turkish)