Did You Sign a Rent Increase Protocol With Your Tenant? You May Be Putting Your Right to File a Rent Determination Lawsuit at Risk

Many landlords who believe the rent has fallen below the market rate prefer to reach an agreement with their tenant without going to court, signing an "additional protocol" between themselves. These protocols typically include gradual rent increases along with a commitment not to file a lawsuit until a certain date. However, such protocols can seriously limit the right to file a new rent determination lawsuit in the future. In this article, we examine how the "equity and fairness" (hak ve nesafet) lawsuit under Article 344/3 of the Turkish Code of Obligations (TCO) is affected by such protocols, and what landlords need to watch out for.

Summary of the Situation

In a commonly encountered scenario, in a tenancy relationship that began years earlier, a landlord who believes the rent has remained low files a rent determination lawsuit. While the case is pending, the parties sign an additional protocol to settle: the rent will be increased gradually, and in return the landlord will not file a new rent determination or adaptation lawsuit until a certain date. As the period set in the protocol nears its end, the landlord considers filing a new rent determination lawsuit based on the "equity and fairness" principle under TCO Article 344/3. This is precisely where two critical legal questions arise.

The Legal Issue

• Is the commitment in the protocol "not to file a lawsuit until a certain date" legally binding?
• Does the additional protocol signed between the parties restart the five-year statutory period under TCO Article 344/3 from its own date, or does the period continue to run from the date of the original lease?

What Does the Court of Cassation Say?

A covenant not to sue is binding under the principle of pacta sunt servanda (ahde vefa). According to the Court of Cassation, 11th Civil Chamber (E. 2010/10339, K. 2012/2322, T. 2012), waiver statements contained in a settlement protocol signed between the parties are binding under the principle of pacta sunt servanda and render the lawsuit moot. Similarly, according to the Court of Cassation, 6th Civil Chamber (E. 2012/8227, K. 2012/10657, T. 2012), the provisions of an additional protocol are valid within the scope of freedom of contract and bind the parties. According to the Court of Cassation, 3rd Civil Chamber (E. 2025/2623, K. 2025/3930, T. 2025), lawsuits filed (prematurely) before the statutory or contractual periods have expired must be dismissed sua sponte on the ground that they were not filed in time.

Protocols that are not aligned with market rates may not reset the period. This is where matters become more complex. According to the Court of Cassation, 3rd Civil Chamber (E. 2017/5793, K. 2019/1589, T. 2019), if the rent in a renewal agreement (protocol) determined by the parties' joint will is not consistent with comparable and market rates, then even if only a few years have passed since the protocol, a determination based on equity and fairness may be requested by taking into account the period elapsed since the start of the original lease. Similarly, according to the Ankara Regional Administrative Court of Justice, 15th Civil Chamber (E. 2023/3794, K. 2023/3188, T. 2023), where the rent has not been increased in line with the market rate, subsequent agreements cannot be regarded as a "new contract," and the five-year period is calculated from the original contract.

However, if the protocol is aligned with market rates, it may be treated as a "new determination." According to the prevailing view in legal doctrine, where the parties determine the rent in line with current market rates through mediation or a protocol, the five-year period under TCO Article 344/3 begins to run anew from the date of that protocol. In this case, a new equity-and-fairness lawsuit cannot be filed until five years have passed from the date of the protocol.

Notice periods must not be overlooked. Under TCO Article 345/2, for the rent determined in a rent determination lawsuit to be valid from the start of the new rental period, written notice must be sent at least 30 days before the start of the new period, or the lawsuit must be filed within that period. If this period is missed, even an accepted determination will only take effect from the following rental period.

Points to Watch

• Assess whether the amount in the protocol is aligned with the market rate. This is the most critical factor in determining both whether the protocol will be treated as a "new determination" and from which date the five-year period runs.
• Comply with the covenant not to sue. A lawsuit filed before the commitment period expires carries the risk of procedural dismissal for lack of legal interest or due to the contractual prohibition.
• Plan the notice period and the filing period together. The duration of the prohibition on filing suit may overlap with the 30-day notice period under TCO Article 345; in that case, strategic timing is required.
• Do not neglect the mandatory mediation requirement. Applying to mediation is a mandatory precondition before a rent determination lawsuit can be filed.

Conclusion: What Should You Do?

An additional protocol signed with a tenant, even if entered into in good faith, can significantly determine the fate of a future rent determination lawsuit. Before filing a lawsuit, the following must be assessed: Has the period of the covenant not to sue in the protocol expired? Was the amount set in the protocol aligned with the market rate at the time it was signed, or was it merely a temporary improvement? The answers to these questions determine both whether the lawsuit will be accepted and from which date the five-year period is calculated. Since incorrect timing can lead to a loss of both time and litigation expense, it is strongly recommended that you consult a rental law attorney before signing a protocol or before filing a lawsuit after signing one.