New offices open to the public: category W, accessibility, fire safety and the environmental regulations

Category W, administrative establishments, covers offices that receive outside users: government offices, bank branches, professional practices receiving clients. It is subject to the fire safety regulations for buildings open to the public, to review by the safety commission, and to the enhanced accessibility requirements that apply to such buildings. A head office closed to the public, or a floor let to a single company, falls only under the Labour Code and, above 50 metres, under the high-rise regulations.

The boundary is not always clear-cut. A reception hall where visitors are always escorted is not usually enough to tip the building into the public-access regime, whereas a freely accessible waiting area is. Where there is any doubt, the safety commission's position should be sought before the planning application goes in, because a late reclassification adds several points to the cost of the project.

ℹ Category W against a private office building Category W: public access, safety commission, full accessibility requirements, the fire safety regulations for buildings open to the public. Private office building: articles R4227 and following of the Labour Code, accessibility under the Labour Code for circulation routes and sanitary facilities. Mixed building, public access at ground floor and private offices above: the public-access rules for the relevant parts, with fire compartmentation towards the private parts.

An office building over 40 m² of gross floor area requires planning permission, determined in three months, extended where the heritage architect has to give an opinion. Schemes inside a protected setting, or subject to an opinion under the classified installations regime for any attached warehousing, should allow one to two further months.

The gross floor area determines the number of parking spaces the local plan requires, often one space per 30 to 60 m². On a constrained urban site that standard frequently forces a basement car park, at between 20 000 and 40 000 € per space including excavation, structure and equipment. It is the first item to check at feasibility stage, before any question of classification.

For office buildings not open to the public, fire safety is set by articles R4227-1 to R4227-57 of the Labour Code and by the 1980 circular on escape routes. The requirements cover the fire resistance of the structure, smoke extraction, means of firefighting and the width of escape routes. For a category W building these rules are cumulative with the public-access fire safety regulations, which are more demanding on smoke extraction and on the fire alarm system.

ℹ Fire safety requirements in workplaces Fire resistance of floors: REI 60 between storeys, REI 120 in basements. Compartmentation of higher-risk rooms, archives and server rooms: REI 60 walls with an EI 60 door. Escape routes: at least two units of width, that is 1,20 m, up to 100 people, and three units from 101 to 200 people. Smoke extraction: compulsory for rooms over 300 m² and for corridors of 30 m or more without natural ventilation. Automatic detection: recommended by insurers under the APSAD R7 rule, compulsory only in particular cases.

Category W buildings must comply in full with the accessibility requirements of the 2014 order. From the first to the fourth category the whole building must be accessible. In the fifth category only part of it need be adapted, provided that every service can be offered to disabled people within that accessible part.

The environmental regulations apply to new offices whose planning application was made from 1 July 2022. The energy demand, primary energy and embodied carbon indicators are set at thresholds specific to commercial buildings, distinct from those for housing. The separate obligation to reduce energy consumption applies only to existing commercial buildings over 1 000 m², but it has to be anticipated in the design where the building is intended to be let.

ℹ Points to watch on a new office building Cooling: a floor plate with high internal gains, IT equipment and dense occupation, generates a cooling demand well into the shoulder seasons, which has to be carried in the environmental assessment. Embodied carbon: a conventional concrete structure struggles to meet the 2025 to 2028 thresholds, and low-carbon concrete or a concrete-and-timber hybrid has become the usual answer. Lighting: the consumption thresholds make LED effectively compulsory, at a reference installed power of 2,5 W/m². Glazing: beyond 50 % of the façade the energy demand indicator degrades sharply, which calls for external shading or selective glazing with a solar factor of 0,32 or less.

An office building is one of the hardest building types to price, for three reasons that compound one another: the variability of the specification, from an economical office to a premium building, the weight of the services packages in the total, and the diversity of the briefs, between open-plan floors, cellular offices, meeting spaces and embedded technical rooms.

ℹ ✔ Economist's summary, new office building Construction cost of a standard office building, excluding land and external works: 1 530 to 2 550 €/m². Premium office, curtain walling, double skin, high-end interior fit-out: 2 550 to 4 080 €/m². In category W, allow for the safety commission, the safety file, the extra cost of accessibility and enhanced acoustic treatment. Basement parking: 20 000 to 40 000 € per space. If the building exceeds 1 000 m² and will be occupied by third parties, the energy reduction obligations feed back into both the design and the leases.

The classification of buildings open to the public, the safety commission and the opening file are covered in the article on public-building regulations. Accessibility has its own article, as do the environmental regulations. Private office buildings, not open to the public, are the subject of a separate article, and office towers above 50 metres fall under the article on high-rise buildings.

ℹ The construction economist on demand. Your office or commercial building deserves an estimate that combines the public-access rules, the environmental regulations and the Labour Code. Submit your brief on quostra.com; an economist prices the regulatory impacts from concept stage.

Reference base for the figures

The rates per m² and per unit on this page are expressed at January 2026 values. They have been updated from January 2025 values, the base adopted for the whole cluster, using the BT01 all-trades index published monthly by INSEE, 2010 base: 132,0 in January 2025 and 134,7 in January 2026, a coefficient of 1,0205.

The lump sums quoted as examples remain at their base: a building cost index does not apply to them.

To bring the rates forward, apply the usual formula: updated value = the value on this page × (BT01 for the month in question / 134,7). BT01 measures contractors' input costs, 44,9 % labour and 36,5 % materials, not the prices actually returned at tender.

• construction regulations in France
• public building classification
• private office buildings
• accessibility requirements