The tertiary decree is entering a phase where a simple declaration on OPERAT is no longer sufficient. Since July 1, 2026, the Eco Energy Tertiary certificate has become an enforceable document, attached to leases and sales agreements. For owners and operators of tertiary-use buildings, preparing for the deadline of September 30, 2026, requires a precise understanding of what has changed in the system.
Eco Energy Tertiary Certificate: What Changes Since July 2026
The regulatory framework of the tertiary decree has undergone a discreet yet structuring shift. The order of August 1, 2025, published in the Official Journal in September 2025, ended the transitional phase during which the OPERAT certificate remained provisional or optional.
Since July 1, 2026, the certificate must be displayed in each affected building, in a location visible to the public or occupants. It must also be attached to each tertiary lease and each sales agreement concerning the affected building.
This change in status transforms the certificate into a contractual document. A buyer or tenant can now rely on it to assess the energy compliance of the building. For landlords, the absence of attachment poses a legal risk in real estate transactions. It is no longer an internal indicator; it is an enforceable document, as noted by the definition on Décideur in its analysis of the legal obligations of the system.
OPERAT Declaration by September 30, 2026: Beyond Data Entry
The date of September 30, 2026, corresponds to the annual deadline for declaring energy consumption on the OPERAT platform. This year, the declaration carries a particular significance: the regulatory tolerance on digital certificates has expired.
Before July 2026, an obligated party could simply fill in their consumption data without the certificate produced having any real legal weight. This is no longer the case. Compliance is now measured by the quality of the declared data, the consistency of the chosen reference year, and the displayed reduction trajectory.
Field feedback varies on this point: some managers of tertiary parks believe their historical data is reliable enough, while others discover inconsistencies when consolidating readings from multiple sites. Pre-verification of the declaration campaign has become a full-fledged step, not just a last-minute check.
Reference Year and Calculation Method: Choices that Commit
The tertiary decree allows obligated parties to choose between two methods to set their final energy consumption reduction targets:
- The relative method, which involves comparing current consumption to that of a reference year specific to the building (any year after 2010 can be selected)
- The absolute method, which requires reaching a consumption threshold set by order based on the building’s activity category
- The possibility of modulation, governed by a technical file, for buildings facing architectural, heritage, or technical constraints that make standard objectives difficult to achieve
The choice of the reference year conditions the entire trajectory. A year of high consumption makes it easier to achieve targets in relative terms but exposes one to a discrepancy if the data is unreliable. A recent year, post-renovation, can conversely make the target of -40% by 2030 very difficult to meet.
For buildings whose activity has changed or whose tertiary area has been reconfigured, the question of consistency between the reference year and the current scope remains a technically underestimated point. The data available on OPERAT does not always allow for reconstructing a reliable history for buildings that have changed ownership or use.
Modulation: A Demanding Procedure
Modulation is not an automatic exemption. The technical file must demonstrate, with supporting evidence, that the invoked constraints prevent reaching the regulatory thresholds. The three admissible reasons (technical, architectural, or related to a change in activity) each require specific justifications.
A poorly substantiated modulation file will be rejected, and the obligated party will remain subject to the initial targets. The rigor of data collection in advance (energy audits, consumption readings, structural diagnostics) determines the admissibility of the request.
Sanctions and Controls of the Tertiary Decree: Announced Intensification
The system provides for a mechanism of sanctions for obligated parties who do not comply with their declaration obligations or who do not undertake reduction actions. The sanction regime is based on:
- A formal notice by the prefect in case of non-declaration or manifestly inconsistent declaration on OPERAT
- The publication of the names of companies or local authorities in non-compliance (the principle of “name and shame”)
- Administrative fines that can reach significant levels for legal entities
The intensification of controls is gradual. The first verification campaigns primarily target large tertiary surfaces and obligated parties who have not made any declarations. In contrast, buildings that declare but whose reduction trajectory remains insufficient are currently subject to less stringent monitoring.
This gradation should not obscure the reputational stakes. The publication of the names of non-compliant obligated parties poses a risk to the image of companies and local authorities, sometimes more deterrent than the fine itself.
The tertiary decree is no longer a voluntary declaration system. The enforceable certificate in leases, the end of the transitional period, and the gradual strengthening of controls place obligated parties in front of concrete obligations. For buildings with fragmented consumption data or whose reference year has never been formally validated, the campaign of September 30, 2026, represents the first real test of compliance.
