INTRODUCTION
The reinstatement claim, which forms the basis of the employment security regime, is one of the most important legal mechanisms aimed at protecting employees against dismissal under the Labor Law No. 4857 (“LL” or “Labor Law”). Pursuant to the provisions introduced by the Labor Courts Law No. 7036 (“LCL” or “Labor Courts Law”), the assertion of a reinstatement claim is subject to a procedural requirement mandating recourse to mediation prior to filing a lawsuit. In this respect, mediation has become not only an alternative dispute resolution method in reinstatement disputes, but also a procedural institution that serves as a prerequisite for access to the courts.
However, the application of the mediation requirement as a condition for filing a lawsuit has given rise to significant debates, particularly in cases involving principal employer–subcontractor relationships, regarding the determination of the parties. The regulation requiring the principal employer and the subcontractor to be jointly identified as parties and to participate jointly in the mediation process when applying to a mediator with a reinstatement claim imposed on the employee the obligation to resolve a complex employer relationship without a judicial determination having yet been made. This situation could lead to consequences directly affecting the essence of the right to reinstatement, such as the dismissal of the case on procedural grounds due to a formal deficiency in the conditions for bringing the case.
The Constitutional Court’s decision dated 03.06.2025 and numbered 2024/157 E., 2025/121 K. (“Decision”) constitutes an important precedent in this regard, re-examining the established practice regarding the mediation process in reinstatement disputes within the framework of constitutional principles. The Decision evaluates the requirement for the principal and subcontracting employers to be joint parties during the mediation phase in reinstatement cases in terms of the right of access to court, the principle of proportionality, and the employee’s ability to effectively exercise their right to sue, and concludes that this requirement is incompatible with constitutional guarantees.
This article will examine the requirement for the principal and subcontracting employers to be joint parties in mediation in reinstatement disputes in light of the Decision, considering the purpose of mediation as a condition for litigation, the procedural burden it imposes on the employee, and its potential effects on practice.
LEGAL FRAMEWORK
General Framework of Mandatory Mediation in Reinstatement Disputes
A reinstatement claim is a type of lawsuit based on the allegation that the employment contract was terminated without valid cause under the Labor Law and is subject to strict time limits. Under the litigation prerequisite mediation system introduced by the Labor Courts Law, an employee must first apply to a mediator before they can pursue a reinstatement claim. This regulation aims to resolve disputes before they reach the courts and to reduce the workload of the courts.
However, it is not possible for the condition of mediation to be applied in a manner that would eliminate the right of access to the courts or make the exercise of this right excessively difficult. Indeed, the prerequisite nature of mediation has procedural law consequences; therefore, formal deficiencies in the mediation process may lead to the termination of the case without addressing the substance of the dispute. This situation is particularly sensitive in the case of claims subject to time limits, such as reinstatement.
The Obligation of the Principal and Subcontractor to Participate in the Mediation Process Together
The principal-subcontractor relationship involves structural complexity in labor law, as the workplace where the employee actually performs their labor does not always correspond to the employer to whom they are legally bound. In terms of daily work routine, the relationship of receiving instructions, and work organisation, the employee often works at the principal employer’s workplace and under their supervision; however, the employment contract may be legally established with the subcontractor. This separation directly affects issues such as which employer has the power to terminate the contract in reinstatement claims, who is responsible for fulfilling the obligation to hire, and which employer is liable for any financial consequences that may arise. This is because, in most cases, whether this relationship constitutes a lawful principal-subcontractor relationship or a sham arrangement can only be determined through the evaluation of evidence during the trial process.
In this context, the regulation requiring the principal and subcontractor to be jointly named as parties during the mediation phase imposes on the employee the obligation to correctly identify a complex and technical legal relationship before any judicial review has taken place. It is not always possible for the employee to foresee the content of the subcontracting agreement, to which they are not a party, the legality of the relationship, or the existence of a possible sham arrangement at the stage of applying for mediation. Therefore, if the employee only included the employer with whom they were actually dealing in the mediation, the application could be deemed incomplete on the grounds that the condition for the lawsuit had not been met, and the reinstatement lawsuit could be dismissed on procedural grounds without entering into the merits of the case.
This practice has led to consequences that are difficult to remedy for the employee, especially considering that the reinstatement claim is subject to strict time limits. Accepting that the condition for bringing a claim has not been met due to a formal deficiency effectively eliminates the employee’s ability to reapply for mediation and then file a lawsuit in most cases; thus, the right to reinstatement ends without ever being examined in terms of substantive law. In this respect, the requirement to be a party has become a serious procedural obstacle that goes beyond the dispute resolution function of mediation and limits the right of access to the courts.
Constitutional Assessment of the Decision
In its decision, the Constitutional Court examined the mediation process, which is a prerequisite for litigation in reinstatement disputes, within the framework of the “right of access to court” guaranteed by Article 36 of the Constitution. While acknowledging that mediation as a condition for filing a lawsuit falls within the discretion of the legislature, the Court also assessed whether the exercise of this discretion imposes disproportionate restrictions on fundamental rights and freedoms. In this context, it was clearly established that the requirement of joint participation constitutes a restriction on the right of access to court.
Indeed, the Decision explicitly stated that the contested regulation “imposes a restriction on the right of access to the courts by requiring joint application to a mediator against both the principal employer and the subcontractor in order to file a reinstatement lawsuit.“ The Constitutional Court examined whether this restriction complies with the principle of proportionality under Article 13 of the Constitution and stated that the restriction must be assessed in terms of the sub-principles of suitability, necessity and proportionality.
In its proportionality review, the Court accepted that the obligation to jointly apply to a mediator against the principal employer and the subcontractor was aimed at preventing issues relating to party status and ensuring the participation of all employers whose interests were affected in the mediation process. However, the Court examined whether less burdensome procedural means were available to achieve this purpose, drawing particular attention to the existence of mechanisms allowing for a change of parties during the trial phase. In this context, the Decision stated that it is possible to ensure the formation of parties during the trial phase by “allowing a change of parties in a reinstatement case that cannot be directed to the correct party by an employee who is unaware of the principal-subcontractor relationship or who does not know that this relationship is invalid or based on collusion”; therefore emphasising that formal deficiencies during the mediation stage cannot be interpreted as eliminating the right to sue.
In contrast, the Decision clearly states that the requirement to be joint parties during the mediation phase has serious consequences for the employee. The Court stated that “the rule requiring the mediation process to be conducted jointly against the principal employer and the subcontractor by determining the legal relationship between the principal employer and the subcontractor, to which the employee is not a party, imposes an unbearable burden on the employee seeking reinstatement.” In line with this assessment, the Decision stated that a reasonable balance could not be struck between the public interest in preventing problems relating to party status in the proceedings and ensuring that the principal employer and the subcontractor jointly participate in the mediation process, and the individual interest of the employee in exercising their right of access to the courts.
In line with these constitutional assessments, the Decision ruled by a majority vote that “paragraph (15) of Article 3 of the Labor Courts Law No. 7036 is unconstitutional and shall be repealed.“ Thus, the provision requiring the principal and subcontractor to be joint parties during the mediation phase in reinstatement disputes has been repealed.
Effects Of The Decision On Practice
The most direct effect of the decision will be seen in the practice of determining the parties in the mediation process, which is a prerequisite for litigation in reinstatement disputes. Prior to the repeal of the regulation, where a principal-subcontractor relationship existed, the employee was required to direct their mediation application against both employers jointly; failure to fulfil this obligation could result in the case being dismissed on procedural grounds without examination of the merits. With this decision, this obligation has been removed; it is now sufficient for the employee to direct their mediation application to the party they dealt with in the termination or the party they actually consider to be the employer in order to fulfil the condition for the case.
This change is of great importance in practice, particularly because reinstatement claims are subject to strict time limits. This is because, in the previous practice, if an error was made in identifying the party during the mediation phase, it was often impossible for the employee to reapply for mediation and file a lawsuit; this situation led to the right to reinstatement ending without any substantive legal examination. Following the decision, however, the interpretation of formal deficiencies in the mediation process as eliminating the right to sue has been prevented, creating a more favourable ground for judicial examination of the substance of disputes.
On the other hand, the Decision reinforces an approach that leaves assessments of the legal nature of the principal employer-subcontractor relationship to the judicial process rather than the mediation stage. Accordingly, issues such as whether the relationship constitutes a valid subcontracting relationship or a sham arrangement, who has the power to terminate the contract, and which employer is responsible for the obligation to hire, will be determined by the court through the collection and evaluation of evidence. This approach clarifies the distinction between the function of mediation and the function of adjudication.
The Decision is also expected to influence how courts handle objections related to mandatory mediation. Instead of considering deficiencies in determining the parties during the mediation process as an absolute procedural obstacle, courts will need to interpret them within the framework of the right of access to court and the principle of proportionality. In this context, the Decision constitutes a precedent that prevents the application of mandatory pre-trial mediation as an absolute procedural obstacle against the employee in reinstatement disputes and guides its application.
CONCLUSION
While the application of mandatory mediation in reinstatement disputes aims to resolve disputes before they reach court, it has entailed significant procedural risks for employees, particularly in cases involving principal-subcontractor relationships, with regard to determining the parties. The regulation requiring both employers to be jointly designated as parties during the mediation phase imposed on the employee the obligation to resolve a complex employer relationship without a judicial determination having yet been made; this situation could lead to the case being dismissed on procedural grounds without the merits of the reinstatement claim being examined.
The Constitutional Court’s Decision dated 03.06.2025, numbered 2024/157 E., 2025/121 K., which found the aforementioned requirement to be contrary to Articles 13 and 36 of the Constitution and annulled it, has created a significant transformation in the application of mandatory mediation. The Decision clearly states that, based on an assessment made within the framework of the sub-principles of the principle of proportionality in terms of the effective exercise of the right of access to the courts, formal deficiencies in the mediation process cannot result in the elimination of the right to bring a lawsuit.
In this context, the Decision confirms that the mediation stage in reinstatement disputes is not a phase in which all disputes regarding party status are definitively resolved; rather, determinations regarding the existence, validity, or fraudulent nature of the principal-subcontractor relationship must essentially be made during the trial process. Thus, the pre-trial mediation requirement has been prevented from becoming an absolute procedural obstacle for the employee; a clear constitutional framework has been established, stipulating that courts must evaluate this process in light of the right of access to court and the principle of proportionality.
