What is the Role of an Interior Designer?
by Leslie Alexander, Co-Founder / Director
Table of Contents
What is an Interior Designer?
Transforming a dated Parisian apartment into a functional and aesthetic living space doesn't happen by chance. An interior designer is the professional who designs, draws and coordinates the layout of interior spaces, as defined by Article 4 of the French Architecture Law of January 3, 1977. Their intervention goes far beyond simply choosing colors or furniture: they orchestrate the complete transformation of your home, from room layout to optimizing every square meter.
In France, the interior design market represents between €15 and €25 billion in annual turnover, with steady growth of 3 to 6% per year. This dynamism reflects the growing importance placed on living environment. However, faced with the complexity of renovation projects – technical constraints, regulations, contractor coordination – homeowners rarely appreciate the full scope of skills required.
This article sheds light on the concrete missions of an interior designer, the legal framework governing their practice and the guarantees they provide. You will understand why hiring a qualified professional is a protective investment for the success of your renovation or interior design project.
What are the missions of an Interior Designer?
Project analysis and design
The interior designer is involved in the entire process of transforming a space, from complete interior renovation to simple reorganization. Their mission begins with a phase of listening and analyzing the client's needs, called the project owner in professional jargon. They evaluate the technical constraints of the space: load-bearing structure, existing networks, natural light and applicable regulations.
Next comes the design phase, where the interior designer develops plans, perspectives and 3D visualizations. They propose layout solutions and volume optimization, rethink circulation, integrate custom storage and select materials suited to your project. This creative stage is accompanied by rigorous technical work: feasibility studies, execution plans and detailed specifications.
Project management and site supervision
Beyond drawing, the interior designer often provides project management, meaning coordination and site supervision. They select contractors, verify compliance of work and ensure respect for budget and deadlines. According to the French Council of Interior Architects (CFAI), the mission ends when all reservations made during handover are resolved.
What qualifications and legal guarantees for an Interior Designer?
The CFAI title: recognized competence
Unlike licensed architects, the interior design profession is not regulated in France to date. However, the title "CFAI Interior Designer" is protected and reserved for professionals recognized as competent by the French Council of Interior Architects. This certification requires either a diploma from a recognized school plus three years of experience, or validation of a professional track record before a commission.
The 10-year warranty: your legal protection
This distinction is crucial for the client. A CFAI interior designer is mandatorily insured for their missions, particularly under the 10-year liability. Article 1792 of the French Civil Code, reinforced by the Spinetta Law of January 4, 1978, establishes that any builder of a structure is liable by law for damages compromising the solidity of the work or making it unfit for its intended purpose.
Concretely, this 10-year warranty covers for ten years any disorders affecting the structure or inseparable elements (embedded pipes, floors, etc.). For the project owner, choosing an insured professional is not a luxury but essential protection against defects and potential disputes.
Interior Designer, Decorator or Architect: what differences?
Confusion between these professions is common, but their scopes of intervention differ fundamentally. The decorator works only on furnishing and decorative finishes, without touching the building structure. Their work requires no modification of existing walls, floors or ceilings.
The interior designer, on the other hand, designs and carries out structural work inside buildings: moving partitions, creating mezzanines, completely reorganizing rooms. According to the CFAI, their activity covers everything concerning the act of creating and designing interior spaces. They generally exercise a project management function.
As for the licensed architect (DPLG or HMONP, registered with the Order of Architects), they alone are authorized to work on load-bearing structures and exterior facades. For projects over 150 m² requiring a building permit, their intervention becomes mandatory. In practice, architects and interior designers frequently collaborate on complex projects, each bringing their complementary expertise.
Comparison Table
| Criteria | Decorator | Interior Designer | Licensed Architect |
|---|---|---|---|
| Required training | None mandatory | 4-5 years (CFAI) | 6 years mandatory |
| Building work | No | Yes (interior) | Yes (int. + ext.) |
| Moving partitions | No | Yes | Yes |
| Load-bearing structure work | No | No | Yes |
| Building permit (+150 m²) | Not authorized | Not authorized | Mandatory |
| 10-year warranty | No | Yes (if CFAI) | Yes |
| Average fees | €50-150/h | 10-15% of budget | 8-15% of budget |
Why hire an Interior Designer for your project?
Secure your renovation project
Renovation projects involve risks underestimated by homeowners. In 2024, 53% of interior designers reported a decline in revenue, according to the Houzz 2025 Barometer, reflecting a climate where some clients try to manage their work alone to save money. This approach often leads to cost overruns and significant inconvenience.
A qualified professional anticipates technical problems that the novice will discover during construction: electrical standards, non-compliant drainage, hidden structural constraints. They legally secure the project through their professional insurance and contracts defining the responsibilities of each party during work coordination.
Optimize your budget and timelines
Moreover, the interior designer optimizes your budget by avoiding costly mistakes and negotiating with contractors. Their fees, generally between 10 and 15% of the project cost, often include the guarantee of a result that meets your expectations. To obtain an interior designer quote, it is recommended to consult several professionals to compare rates and included services.
- Designer fees
- 10-15%
- Savings achieved
- 20-30%
- Warranty coverage
- 10 years
For a Parisian apartment where the price per square meter exceeds several thousand euros, this expertise represents a quickly profitable investment.
How to find the right Interior Designer in Paris?
Faced with the complexity of an interior design project – technical work, regulations, contractor coordination – surrounding yourself with a competent professional is not a luxury but a necessity. The financial stakes and legal guarantees involved fully justify this approach.
Hauss Paris supports individuals and professionals in their interior design projects in Paris. As a specialized intermediary, we facilitate the meeting between your project and an interior designer suited to your needs, style and way of working. Renovation of Parisian apartments, volume optimization, office or commercial space design: from studio to large Haussmann apartment, we help you move forward with confidence.
Our human and structured approach ensures coherent collaborations, serving a demanding French and international clientele. Contact Hauss Paris to transform your vision into reality, with the assurance of benefiting from the skills and guarantees of a qualified professional.
FAQ: Your questions about Interior Designers
How much does an interior designer cost?
Interior designer fees vary according to the type of mission. For a complete mission (design + site supervision), expect between 10 and 15% of the total project cost. For consulting or design-only services, rates range from €80 to €200 per hour depending on the professional's experience and location (Paris being generally more expensive). Some interior designers also offer packages for specific services.
What is the difference between an architect and an interior designer?
A licensed architect (DPLG/HMONP) can work on the building's load-bearing structure and exterior facades. The interior designer focuses on interior design: non-load-bearing partitions, layout, space optimization, material selection and site supervision. For projects over 150 m² requiring a building permit, only a licensed architect is authorized to submit the application.
Is it mandatory to hire an interior designer for renovation?
No, it's not a legal requirement. However, hiring a CFAI-certified interior designer guarantees technical expertise, professional insurance (including 10-year warranty) and rigorous site supervision. For work affecting the building structure (moving partitions, creating mezzanines, etc.), their intervention is strongly recommended to avoid defects and disputes.
How to verify if an interior designer is qualified?
Check if the professional is registered with the CFAI (French Council of Interior Architects) via their online directory at cfai.fr. Also request an up-to-date certificate of professional liability and 10-year warranty insurance. A CFAI interior designer has a professional card renewed annually after verification of their insurance.
Sources: French Council of Interior Architects (CFAI), Légifrance, Houzz 2025 Barometer