Partner Hamburg
"The ruling is relevant for energy companies and other stakeholders in the energy sector, as long-term commercial leases and usage agreements often include value preservation clauses that play a key role in securing long-term investments."
On 5 June 2025, the Higher Regional Court of Düsseldorf (“OLG Düsseldorf”) (Ref.: 10 U 146/24) answered the important question concerning parties to a commercial lease agreement as to whether standardised index clauses in commercial tenancy law are subject to review under the statutory general terms and conditions, even though they also subject to a review of the Price Clause Act (“PrKG”).
The OLG Düsseldorf confirmed that a breach of the requirements of the statutory general terms and conditions, particularly the transparency requirement, would render the index clause invalid from the outset (ex tunc). This decision marks a stricter interpretation of the requirements for drafting index clauses. Indexation clauses that link rent payments to the development of the consumer price index (“CPI”) are a regular feature of long-term commercial leases and serve to protect the capital value of the property against inflation.
The ruling is relevant for energy companies and other stakeholders in the energy sector, as long-term commercial leases and usage agreements – for example, for operating sites, network infrastructure or technical facilities – often include value preservation clauses that play a key role in securing long-term investments.
Background
In August 2019, the parties entered into a commercial lease agreement with a lease commencement date of 1 September 2019 and an agreed fixed term of ten years. The lease agreement contained an index clause, according to which the rent was to be adjusted ‘automatically’ with reference to the development of the CPI based on the index level in May 2017. The rent was initially fixed for two years. An initial change in the rent was to take effect after a written request from the landlord. This clause was to apply accordingly to future rent adjustments. The tenant considered the index clause to be invalid, paid the rent adjustments subject to reservation and demanded repayment from the landlord. The OLG Düsseldorf upheld the tenant’s claim in the first instance and declared the index clause to be invalid from the outset.
"The ruling of the OLG Düsseldorf confirms the legal opinion already expressed by the Federal Court of Justice (Bundesgerichtshof “BGH”) in other areas (e.g. energy supply contracts) that standardised index t clauses are subject to both control under the PrKG and a review under Sections 307 et seq. of the German Civil Code (“BGB”)."
The defendant landlord appealed against the judgment, taking the legal view that the index clause is valid under the PrKG and that a review of general terms and conditions therefore does not apply. The PrKG is lex specialis and therefore excludes a review of general terms and conditions. In its ruling of 5 June 2025, the OLG Düsseldorf dismissed the landlord’s appeal and upheld the first-instance decision.
Application of content control and different legal consequences
The ruling of the OLG Düsseldorf confirms the legal opinion already expressed by the Federal Court of Justice (Bundesgerichtshof “BGH”) in other areas (e.g. energy supply contracts) that standardised index t clauses are subject to both control under the PrKG and a review under Sections 307 et seq. of the German Civil Code (“BGB”). Neither the wording of the provisions of the PrKG nor the purpose of the PrKG indicate that its provisions are intended to be exhaustive and exclude a review under general terms and conditions.
The question of whether the index clause is also subject to review under Section 307 BGB is significant because of the different legal consequences – with resulting significant economic consequences for the parties.
Section 8 PrKG stipulates that, in the event of an index clause being invalid, the legal consequence is that the provision is invalid for the future from the date of the final court ruling on the violation.
However, if an index clause (also) fails to withstand a content review pursuant to Section 307 BGB, this leads to the initial invalidity of the provision. In this case, a tenant can assert a claim for reimbursement against the landlord from the first rent increase in accordance with the value guarantee clause – as in the present decision.
Reasons for the invalidity of the value adjustment clause after content review
According to the OLG Düsseldorf, the index clause does not stand up to a content review.
On the one hand, the OLG Düsseldorf objected to the reference to the base index in May 2017. The clause chose the CPI published by the Federal Statistical Office for May 2017 as the reference point for the calculation. This date was well before the conclusion of the lease agreement and the actual start of fixed term. In the opinion of the OLG Düsseldorf, the clause unreasonably disadvantaged the tenant, as it had to bear inflation increases that had already occurred before the consideration – the transfer of the rented property – was received. The OLG Düsseldorf considers the setting of a base date prior to the start of the tenancy to be a strong indication of unreasonable disadvantage, as it runs counter to the basic idea of Section 2 (3) No. 3 PrKG.
On the other hand, the index clause violates the transparency requirement contained in Section 307 (1) sentence 2 of the German Civil Code (“BGB”). The transparency requirement obliges the user to formulate the rights and obligations of the contractual partner as clearly as possible (and necessary) and to present them in a transparent manner. However, the index clause contains contradictory provisions regarding the effectiveness of the adjustment. On the one hand, the wording stipulated that the rent would change ‘automatically’ in the same proportion as the index. On the other hand, it was stipulated that the change would only take effect ‘after a written request by the landlord’. This contradiction creates a lack of transparency for the tenant, as it is not clear from when the increased rent was due.
Decision of the BGH still pending
The OLG Düsseldorf has allowed an appeal to the BGH, as the question of the interaction between the control of general terms and conditions and the PrKG in commercial tenancy law has not yet been conclusively clarified by the highest court.
"Applying these principles, there are good arguments in favour of tenants having gained knowledge within the meaning of Section 199 BGB with the enactment of this ruling and subsequent rulings, or should have gained such knowledge without gross negligence, so that the three-year standard limitation period could begin at the end of this year or next year."
Effects on practice
Indexation clauses have become increasingly important since 2022 due to rising inflation. The decision shows that these provisions must be drafted in a legally compliant manner. The requirements of the PrKG must be complied with and the provisions must be drafted transparently so that they can withstand a review of their content. In particular, this means that the calculation of the rent adjustment must be comprehensible, the clause must not be contradictory and the clause must not refer to outdated index levels. Referring to an index level that is outdated at the actual start of the tenancy is not uncommon if several years elapse between the conclusion of the contract and the start of the tenancy. This allowed landlords to take price developments during the construction phase into account.
Since many older commercial leases contain value protection clauses that have only regained significance with rising inflation, it is necessary to examine whether rent increases based on these clauses have been effective. Tenants have the option of asserting significant claims for reimbursement from old contracts. Such claims for reimbursement based on unjust enrichment are likely to become time-barred within three years of the end of the year in which the claim for enrichment arose and the tenant became aware of the circumstances giving rise to the claim and the identity of the debtor, or should have become aware of them without gross negligence, in accordance with the standard limitation period pursuant to Sections 195 and 199 of the BGB.
There may well be intense debate about when a tenant acquires knowledge within the meaning of Section 199 BGB, as the legal situation has not yet been decided by the highest court, as shown by the admission of the appeal to the BGH and the contrary decision of 5 February 2024 by the Higher Regional Court of Schleswig (“OLG Schleswig”) (Ref.: 12 U 69/23). In this decision, OLG Schleswig took the legal view that in a comparable case involving an index clause, a review of the general terms and conditions should be rejected due to the special legal review standard of the PrKG. However, a trend is now emerging because of the decision of the OLG Düsseldorf.
In the case of claims for the refund of a processing fee that the lender had stipulated in invalid general terms and conditions, the subjective element of Section 199 (1) No. 2 BGB was fulfilled at the time when a clear tendency towards the assumption of invalidity became apparent in the higher court case law.
Applying these principles, there are good arguments in favour of tenants having gained knowledge within the meaning of Section 199 BGB with the enactment of this ruling and subsequent rulings, or should have gained such knowledge without gross negligence, so that the three-year standard limitation period could begin at the end of this year or next year.
Key contacts
Partner Hamburg
Associate Düsseldorf
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