What the ESQ stage is
Under a loi MOP appointment the esquisse is the first element of the core duties, coming immediately after the briefing stage prepared by the client. It tests whether the brief is compatible with the site, with the planning constraints and with the budget in mind.
On private projects the esquisse takes different forms depending on the client. An experienced developer will supply a precise brief and expect a fast response; a private individual will need the architect's help to define what they actually want before any image of the project can be drawn.
The esquisse presumes no settled technical solutions. It is a stage of intentions and trade-offs: the major options are set, siting, massing, functional organisation, without yet fixing the construction choices, which are settled at APS.
Where ESQ sits in the sequence
| Before ESQ: the brief | The client defines their needs, the budget in mind, the site, the programme and any particular constraints. Without a brief there is no coherent project. |
|---|---|
| ESQ | The first spatial translation of the brief. Architectural feasibility, massing, functional organisation, and a first budget envelope from ratios. |
| After ESQ: APS | Preliminary technical options, an estimate by trade, and a first provisional commitment to the forecast cost. The decision to move to APS is what validates the ESQ. |
The ESQ deliverables
Exactly what the ESQ produces depends on the project and the contract, but the following documents are usual.
Architectural deliverables
- ℹ Principle drawings at 1:200 to 1:500: site plan and schematic floor plans showing the functional organisation. No construction detail at this stage.
- ℹ Massing sketches: perspective sketches or schematic 3D views illustrating the architectural approach.
- ℹ Area note: confirmation that the brief's areas fit within the buildable volume of the site, under the local plan's rules on footprint, height and density.
- ℹ Landscape integration: a view placing the project in its immediate surroundings, often required for a preliminary planning file or a first consultation.
The cost deliverable: an order of magnitude
The ESQ budget is produced by applying cost ratios per square metre of floor area. It is the fastest method and the one suited to this stage, where the project is not defined finely enough to be broken down trade by trade.
Building an ESQ order of magnitude: the ratio method
Step 1, establish the floor area: the regulated floor area, which is the basis of the calculation.
Step 2, choose the right ratio: the ratio depends on the building type, apartments, offices, public-access building, house, on the specification level, standard, mid-range or high-end, and on the geography.
Step 3, apply the ratio: estimated works cost = area × ratio per square metre. That figure is the works cost excluding VAT, excluding land, fees and taxes.
Step 4, build back up to the total development cost: add design fees at around 10 to 12 % of the works, insurance at 0.5 to 1 %, and finance costs where they apply.
The accuracy of an ESQ order of magnitude is in the region of ±25 to 30 %. That is a wide band, but it matches how loosely the project is defined. Its purpose is not to fix the final budget; it is to avoid pursuing design work on a project fundamentally beyond the client's means.
Reference ratios at ESQ
The ratios below are indicative bands in euros excluding VAT per square metre of floor area, for projects in mainland France in average market conditions. They cover construction works only: no land, no fees, no taxes.
| House, standard specification | 1,430 – 1,940 €/m² |
|---|---|
| House, high-end | 2,040 – 3,060 €/m² |
| Apartments, ordinary location | 1,630 – 2,140 €/m² |
| Apartments, dense location or Paris | 2,240 – 3,060 €/m² |
| Offices, standard | 1,530 – 2,240 €/m² |
| Offices, high-end or certified | 2,240 – 3,570 €/m² |
| Public-access: school, nursery | 2,040 – 2,860 €/m² |
| Public-access: indoor sports facility | 1,840 – 2,550 €/m² |
| Light refurbishment, finishing trades only | 610 – 1,220 €/m² |
| Heavy refurbishment, structure and finishes | 1,220 – 2,550 €/m² |
Indicative bands, to be updated against the current BT01 index and the location of the project. Source: professional practice, Widloecher and Cusant.
How an ESQ budget gets under-estimated
Under-estimating the cost at ESQ is one of the most frequent causes of trouble later, at APD and at tender. It produces uncomfortable moments: telling a client, after months of design work and meetings, that their project costs 30 or 40 % more than they were told.
| A ratio that does not fit the project | A standard apartment ratio applied to a public-access building or to a low-energy scheme under-estimates systematically. Every programme has its specifics. |
|---|---|
| Peripheral items left out | External works, landscaping, asbestos removal in existing buildings, special foundations in difficult ground: these can be 10 to 25 % of the total cost and are routinely omitted at ESQ. |
| Site constraints not accounted for | A sloping site, a high water table, complex party walls, clay soil: all of them hard to anticipate without a ground investigation, and all of them things a contingency must cover. |
| Specification not defined | A brief that does not state the specification level, standard or high-end, leads to median ratios that can under-estimate the real cost by 40 to 60 %. |
| A tight market | In periods of strong demand or material inflation, as in 2021 to 2023, historic ratios fall short of real market prices. |
ℹ Good practice: always give a band, never a single figure An ESQ order of magnitude must never be presented as a settled budget. Professional practice is to give a band, say 1.8 to 2.2 M€ excluding VAT, with the reservations stated explicitly: specification level to be confirmed, no ground investigation yet, external works excluded. That wording protects the design team contractually, and it is more honest towards a client who can then anticipate the hazards rather than discover them.
ESQ under a loi MOP appointment
Under loi MOP the ESQ is a distinct element of the appointment, paid for separately. The client's approval of it is what releases the APS stage. The MIQCP guide allocates around 8 % of the core appointment fee to ESQ.
On projects in existing buildings the core loi MOP appointment begins at APS rather than ESQ. The ESQ stage is then replaced by a technical survey of the existing building, paid for in addition to the core appointment.
What Quostra takes on at ESQ
Producing a reliable order of magnitude at ESQ requires current knowledge of market prices by building type, by region and by specification level. Few architectural practices keep such a database permanently up to date.
ℹ Quostra, the construction economist on demand Cost estimates, pricing schedules, developer appraisals, summary notes. The deliverables that take you days today, taken on by a dedicated economist. You have better things to do. Submit your project and an economist takes over. → quostra.com
Sources: Léonard Hamburger, Maître d'œuvre Bâtiment, 3rd ed., Eyrolles, 2016 · Yves Widloecher and David Cusant, Manuel d'analyse d'un dossier de bâtiment, 2nd ed., Eyrolles, 2018.
Reference basis of the figures
The ratios per square metre and per unit on this page are stated in January 2026 values. They were updated from January 2025 values, the basis retained for this whole group of articles, using the BT01 all-trades index published monthly by INSEE on its 2010 base: 132.0 in January 2025, 134.7 in January 2026, a coefficient of 1.0205.
Global amounts quoted in worked examples, along with rents, running costs and revenues expressed per year or per night, stay at their original basis: a building cost index does not apply to them.
To bring the ratios forward, apply the usual revision formula: updated value = page value × (BT01 for the month in question / 134.7). The BT01 measures contractors' input costs, labour at 44.9 % and materials at 36.5 %, not the prices actually tendered.