Tertiary decree: declaring your energy use on OPERAT

Quick answer. The OPERAT declaration is the annual obligation, under the French tertiary decree, to enter your energy consumption on the ADEME platform before 30 September. It applies to tertiary buildings over 1,000 sq m. For the 30 September 2026 deadline, you declare the 2025 consumption, building unit by building unit, with your floor areas and your reference year.

Every autumn, managers of offices, shops, clinics or warehouses get the same reminder: the annual OPERAT declaration is coming. And every year, the same pattern shows up in our files: the declaration is postponed, the energy bills are not gathered, the reference year is not fixed, and the 30 September deadline arrives too fast. Yet a missing or incomplete declaration exposes the company to a formal notice, then a fine.

This practical guide explains how to complete your OPERAT declaration step by step: who is concerned, which data to gather, in what order to proceed, and which traps to avoid. The goal is simple: a complete, consistent declaration, filed on time.

Decree no. 2019-771 of 23 July 2019, known as the tertiary decree, sets an energy-reduction trajectory for tertiary-use buildings with a floor area of 1,000 sq m or more. The obligation falls on the owner and the tenant, depending on how consumption is split. The OPERAT platform, run by the ADEME, centralises declarations and computes each building's trajectory.

The 1,000 sq m threshold is assessed at the level of the building, a set of buildings on the same land unit, or all tertiary areas combined on the same site. An isolated 600 sq m outlet is not subject to it, but several tertiary premises of the same property can cross the threshold once added together.

The declaration is not a mere administrative formality: it feeds the tracking of a reduction trajectory. The decree sets a cut in final energy consumption of 40% by 2030, 50% by 2040 and 60% by 2050, against a freely chosen reference year (after 2009). This is the so-called relative-value method. As an alternative, the obliged party may target an absolute consumption level, set by order according to the activity category.

The reference year is a structuring choice: it is the basis for the 40%, 50% and 60% calculations. An abnormally high consumption year makes the target easier to reach, but it must reflect a real period of 12 consecutive months of operation.

The main cause of blockage is not the platform, it is the lack of ready data. Before entering anything, gather:

• the exact floor area of each subject functional entity (EFA), meaning each tertiary premises concerned;
• the activity category and sub-category of each EFA (offices, retail, healthcare, education, logistics, etc.);
• the reference year chosen and the matching consumption;
• the consumption for the declared year, by energy type (electricity, gas, heat network, fuel oil), from your bills or meter readings;
• the usage-intensity indicators specific to your activity (hours, headcount, volume, depending on the category), which adjust the target.

Gathering these items upfront saves considerable time and limits entry errors.

The OPERAT declaration follows a logical order. Here are the steps to respect for the annual deadline.

1. Check whether you are subject to it: confirm that your building or combined areas reach 1,000 sq m of tertiary surface.
2. Create or retrieve your account on the ADEME OPERAT platform and access your declarant area.
3. Declare your subject functional entities (EFAs): enter each premises, its area, its activity category and sub-category.
4. Fix your reference year and enter the matching consumption, if not already done in prior years.
5. Enter the declared year's consumption, broken down by energy type, from your bills.
6. Fill in the usage-intensity indicators requested for your activity category.
7. Validate the declaration before 30 September and download the annual digital certificate generated by the platform.

Many directors see the OPERAT declaration as just one more constraint with no value. That is a mistake in perspective. The data you enter first serves your own steering: it reveals, building by building, where your energy goes and how much ground remains before 2030. A declaration done seriously becomes a management tool, not just an obligation.

Our recommendation is to handle this topic well before September. Companies that wait until the last minute improvise a poorly chosen reference year, enter rough consumption figures and lose the benefit of a credible trajectory. Anticipating the collection of bills and validating floor areas, from the first half of the year, changes everything.

A services company runs 3 sites in the Paris region: a 1,400 sq m head office, a 900 sq m branch and a 1,200 sq m logistics floor. The director wrongly believes only the 900 sq m branch escapes the obligation and that the rest is secondary. In reality, the head office and the floor each exceed 1,000 sq m and are fully subject to it. With 4 months to the 30 September deadline, no data is ready.

The catch-up takes about 6 weeks: reconstructing 12 months of 2025 consumption by energy across 2 sites, setting a reference year per building, creating the EFAs and entering the indicators. With a concentrated effort, the 2 subject sites are declared on time. The lesson the director keeps fits in one sentence: next year's declaration is prepared in January, not in August.

Failing to declare, or declaring carelessly, is not neutral. In the event of a breach, the authorities first send a formal notice. If it has no effect, the building's consumption can be published on a State website, in a name-and-shame logic. On top of that comes an administrative fine of up to 1,500 euros for an individual and 7,500 euros for a legal entity, per building concerned.

Beyond the fine, the stakes are reputational and patrimonial: a non-compliant, poorly rated or publicly flagged building loses value on the rental market and at resale. OPERAT compliance becomes, in effect, a real-estate quality criterion.

• Firm 30 September 2026 deadline: you declare the 2025 consumption.
• Reference year: a final, structuring choice, to fix once and for all over 12 real consecutive months.
• EFA perimeter: do not overlook combined tertiary areas that cross the 1,000 sq m threshold.
• Data consistency: areas, energies and usage intensities must match from one year to the next.
• Annual certificate: to download and keep as proof of your declaration.

To connect this obligation to your energy-efficiency strategy and your works financing, see our guides on the tertiary decree obligations and the OPERAT timetable and on financing tertiary renovation through energy-saving certificates.

• Combined tertiary areas checked (1,000 sq m threshold)
• Active OPERAT account and clear declarant perimeter
• One EFA created per distinct tertiary premises
• Reference year fixed over 12 consecutive months
• 2025 consumption broken down by energy
• Usage-intensity indicators filled in
• Declaration validated before 30 September
• Digital certificate downloaded and archived