The client's role in a construction project: construction economics in France

The four fundamental responsibilities

Whatever their nature, a local authority, a developer, a private individual, a company, the client assumes four fundamental responsibilities nobody can assume in their place.

Defining the brief	The brief describes the functional, technical and financial needs the building must satisfy. A poorly defined brief produces schemes that do not match expectations and the extra cost of reworking them.
Securing the funding	The client is responsible for funds being available at each step. Unsecured funding is the principal cause of sites stopping abruptly.
Letting the contracts	The client signs the contracts with the design team and the contractors. Their liability is engaged in the choice of providers and in the contractual terms.
Bearing the risk	In the event of a budget overrun, uninsured damage or commercial failure, it is the client who bears the financial consequences.

Public against private clients

The public client

Public clients, the State, local authorities, public bodies, social landlords, are subject to the procurement code when letting their contracts. They must follow strictly framed procedures on competition, publicity and transparency. Their decisions are subject to review for legality.

The private client

Private clients, developers, investors, individuals, companies, are subject to the civil code and to construction law, but enjoy far greater freedom in choosing their providers and negotiating contractual terms. In exchange, they have no access to the subsidised loans reserved to the public sector.

The client's adviser

Where the client lacks the technical, legal or financial competence to fulfil the role alone, they can appoint an adviser. The adviser counsels and assists the client, but does not substitute for them: the decisions always remain the client's. Representing the client, that is acting in their name, requires a mandate: on public contracts, the agent represents the client towards third parties in the exercise of the powers entrusted to it (L2422-10); on a private operation, a delegate acts in the client's name only within the limits of its mandate (Civil Code, art. 1984 and 1989).

Technical adviser	Assists the client in defining the brief, checking the design, monitoring the site and handing over. A building competence.
Financial adviser	Assists in structuring the finance, seeking funding and public support, and monitoring the appraisal.
Legal adviser	Assists in drafting and negotiating the design and works contracts, and in handling litigation.
Sustainability adviser	Assists in defining the environmental objectives, following the certification and measuring the performance of the completed building.

The key decisions and their moment

Approving the brief	Before any design appointment is launched. Once the brief is approved, changes during design carry a rising cost.
Choosing the design team	Through a consultation or a competition. A decision to be taken on objective criteria: references, methodology, fees.
Approving each design stage	At the end of each stage the client formally approves before the architect moves on.
Choosing the contractors	On the basis of the tender analysis supplied by the design team. The client takes the final award decision.
The decision to take handover	Handover is the act by which the client declares that they accept the building, with or without reservations (Civil Code, art. 1792-6). It starts the warranty periods and transfers custody of the building.

On public contracts, the mandate contract can entrust handover to the agent, under the conditions of prior agreement by the client that it sets (L2422-6, 6°, and L2422-7, 4°); on a private operation, a delegate takes handover only if its mandate provides for it (Civil Code, art. 1989).

What the client cannot delegate

Even with a competent adviser, certain decisions remain with the client: the location of the building, the brief, the provisional financial envelope, the funding and "the choice of the process by which the building will be delivered", and therefore any decision to stop or change the brief or to raise the envelope (L2411-1, L2421-1, L2422-5 and L2422-6). An advisory appointment does not confer the power to sign in the client's place. On public contracts, by contrast, a mandate contract can entrust the agent with signing the design and works contracts, after approval of the choice of the successful bidders, monitoring their execution and taking handover of the building, under the conditions of prior agreement by the client that the contract sets (L2422-6 and L2422-7); the agent acts within the limit of the brief and the envelope set by the client (L2422-5). On a private operation, a delegate signs only what its mandate allows (Civil Code, art. 1984 and 1989). A client who signs documents without understanding them is exposed to substantial liability.

The appointments and responsibilities described correspond to the French legal framework in force in 2026.