One signature, several roles
The budget belongs to whoever pays for it. Client-side assistance (assistance au maître d'ouvrage) prepares the decision; it does not take it.
| Party | What they do on cost | Basis | What they do not do |
|---|---|---|---|
| Client | sets the budget envelope, makes the trade-offs, signs contracts and amendments | the contracts it enters into | delegate its decision without a written, limited mandate |
| Architect | designs within the brief and the budget, assists in choosing contractors | Grand-Ducal Regulation of 17 June 1992, Art. 8, 9 and 13 | guarantee a contractor's price |
| Consulting engineer | same professional obligations for its share of the design | same regulation | commit the client |
| Cost consultant | estimates, prepares counter-estimates, checks bills of quantities, tenders and final accounts | its appointment agreement | no specific legal status identified |
| Project manager | organises, schedules, prepares decisions, reports | its appointment agreement | no specific legal status identified |
The client decides
Every new item of expenditure goes through the client. In a private contract, the client authorises a change in writing and accepts its price; in a public contract, the contracting authority (pouvoir adjudicateur) signs the amendment (avenant) and, for a municipality, goes back to the municipal council (conseil communal) when the approved project changes significantly.
The client also chooses the level of support. A private individual often relies on the architect alone; a developer or a municipality frequently adds an independent cost check. The right level depends on the size of the project and on the client's in-house capacity to check a figure.
The architect and the consulting engineer design within the budget
Their budget obligation is written into their code of professional conduct. The Grand-Ducal Regulation (règlement grand-ducal) of 17 June 1992 requires a written, signed agreement "at the latest when the brief has been defined" (Art. 8, unofficial translation), and requires them to submit designs "which remain within the limits of the programme set in the brief and of the budget that follows from it"; any significant change to the programme calls for an additional agreement stating its financial impact (Art. 9).
They also assist the client in choosing contractors, "with a view to carrying out the project on the best terms of price and quality" (Art. 13). Their independence is protected: practising on an independent basis is incompatible with the profession of building contractor (Art. 4 and 5). Independence is not accuracy: an estimate still needs checking.
The cost consultant and the project manager: roles, not statuses
In the texts reviewed, neither the cost consultant (économiste de la construction) nor the project manager (gestionnaire de projet) has a specific legal status. They are therefore defined by their contract: scope, deliverables, dates, limits of the mandate, independence from contractors. What the law does not provide for, the appointment agreement must spell out.
The cost consultant prices and checks: estimate at each stage, counter-estimate, check of the bill of quantities before tender, tender analysis, monitoring of the forecast final cost, preparation of the final account. The project manager organises: programme, flow of decisions, cost dashboard, meeting reports.
Who answers for what
Fees are freely negotiated. By its decision No 2024-E-01 of 25 March 2024, the Competition Authority (Autorité de la concurrence) made binding commitments given by the OAI, the order of architects and consulting engineers: an end to the circulation of the documents setting remuneration, and a reminder to members that they are free to negotiate their hourly rates and fees with public-sector clients. The amounts charged in practice are covered in the article on design fees.
Liability follows the brief. The ten-year liability of architects and contractors bound to the client by a contract for works (louage d'ouvrage) (Civil Code, Art. 1792) says nothing about keeping to the budget, which is a matter for the agreement. Insurance questions are covered in the article on insurance and liability. A practical principle follows from this: a single cost dashboard, kept by a named party and approved by the client at each stage.
The articles in this branch
- The article on the architect, the consulting engineer, the cost consultant and the project manager sets out, for each of them, the role, the contract, what they do and do not guarantee on cost, and how to put the collaboration in writing.
- The article on what the reform of the construction professions would change follows Bill No 7932 and distinguishes what has been announced, what would be voted and what would apply.
This article sets out the rules as they stood on the date of checking and is intended as professional guidance. It is not a substitute for legal advice or for an examination of your particular case.