Which permits does a renovation in Paris need?

The first question to ask: are you touching the outside?

Almost everything follows from that distinction. Works that stay strictly internal — new floors, paint, a kitchen, a bathroom, renewed electrics and plumbing — require no planning formality at all, provided they create no floor area, do not alter the external appearance of the building and do not change the property's designated use category. That covers the majority of the apartment renovations we run.

As soon as the project crosses the façade — a window replaced with a different model, a new opening, a balustrade, a roof light, air conditioning fixed outside — it falls within the scope of a prior declaration. And as soon as it creates floor area, or touches the structure in the context of a change of designated use, it moves up to a planning permit. Be careful not to merge the two registers: planning and co-ownership are two separate authorisations, and a purely internal project may owe nothing to the town hall while still requiring a vote at a general meeting.

No formality, prior declaration or permit: the table.

Two useful clarifications. First, appointing an architect becomes mandatory once total floor area exceeds 150 m² after the works — a threshold quickly reached on an extension or a roof raising. Second, these periods only start once a complete file has been lodged: a request for additional documents issued by the case officer within the first month restarts the clock when those documents arrive. A carefully assembled file is not administrative politeness, it is site time earned.

In Paris, the factor that changes everything: heritage review.

A large part of the Paris fabric sits within the setting of a listed monument or inside a designated heritage area. In those perimeters the file goes to the Architecte des Bâtiments de France, the state heritage architect, whose opinion conditions the authorisation and extends the review by one month. In practice, a simple prior declaration to replace windows moves from one month to two — and the opinion may prescribe precise characteristics: material, profile, colour, glazing divisions, balustrade type.

Good practice is to settle this before locking in the choices, not after a refusal. On period buildings, where the façade and joinery are part of the property's value, the constraint usually aligns with the interest of the project: it is the logic we apply on heritage properties, set out on our hôtel particulier renovation page.

Co-ownership, the consent people forget.

It is the leading cause of delay we see on Paris renovations — well ahead of the town hall. Three situations call for a general meeting resolution:

• Touching common parts — a load-bearing wall, a service duct, a water or drainage riser belongs to the building, even where it passes through your apartment. Opening a load-bearing wall means a vote, a structural engineer's study and, often, sign-off by the building's own architect.
• Altering the external appearance — windows, balustrades, shutters, air conditioning on the façade or in the courtyard: the harmony of the building is a co-ownership matter, even where planning only asks for a prior declaration.
• Creating a new right of enjoyment — absorbing a landing, a light well or a common room: beyond consent, these carry reinforced majority rules.

The critical point is not the vote itself, it is the meeting calendar. One ordinary general meeting a year means a project arriving in May may wait until the following spring, unless an extraordinary meeting is called — and paid for. That constraint belongs in the conversation at the offer stage, not at the quotation stage. Add to it reading the co-ownership rules, notifying the managing agent, providing insurance certificates, agreeing access and protection of common parts, and observing the working hours set by local order in Paris.

Change of destination, change of use.

The two notions are often conflated, yet they answer to different authorities and different files. Change of destination is a planning matter: it describes moving from one category to another — offices converted into a home, for instance — and calls for a prior declaration, or a planning permit where the load-bearing structure or the façade is modified. Change of use is a separate regime, particularly strict in Paris: turning residential premises into something else requires the City's authorisation, sometimes with a compensation obligation.

The direction of travel therefore matters as much as the nature of the change: converting offices into housing restores homes, whereas the reverse removes them from the stock. Our Trocadéro project illustrates the first case — a former law firm of 227 m² in the 16th arrondissement returned to residential use, with sixteen coordinated trades over ten months. On the commercial side, premises receiving the public add their own authorisation, with a safety commission review depending on the category: we cover that in our guide to office renovation in Paris.

The real timeline, from filing to clear title.

An authorisation obtained is not immediately secure. Three sequences follow one another, and only the last one allows a comfortable start:

• The review — 1 month for a prior declaration, 2 or 3 months for a permit, each extended by a month where heritage review applies. Administrative silence generally amounts to tacit consent, for which it is prudent to request a certificate.
• The third-party appeal window — two months from the first day the notice board is properly displayed on site. Display must be continuous and evidenced, usually by bailiff's report at the beginning, middle and end of the period.
• Administrative withdrawal — the authority may withdraw an unlawful decision within three months of granting it.

In a co-owned building, add the wait until the next general meeting. That is why a Paris project subject to a permit is planned several months before the first skip arrives — a framing we detail in our article on how long a Paris renovation really takes.

During and after the works: what still gets filed.

• The site notice board — mandatory from the moment the permission is granted, visible from the public highway, and the starting point of the appeal window.
• The declaration of commencement — filed with the town hall for a planning permit when the works actually start.
• The declaration of completion and conformity — filed at the end of the works; the authority then has a period in which to challenge conformity.
• Development tax — due where floor area is created; it belongs in the budget at the filing stage, not when the notice arrives.
• Insurance — ten-year warranty certificates from every contractor, and the owner's structural damage policy where the works call for one.

The mistakes that cost months.

• Filing an incomplete application — a request for additional documents restarts the review. A well-assembled file is worth several weeks.
• Discovering the co-ownership mid-design — the building rules and the meeting calendar are read before drawing, not after.
• Choosing joinery before the heritage opinion — in protected areas, prescriptions cover material, profile and colour; the choice is made with them, never against them.
• Neglecting the notice board — without proper, evidenced display, the appeal window never starts running. The legal risk stays open long after handover.
• Confusing destination and use — two files, two authorities. Obtaining one does not dispense with the other.
• Sequencing instead of parallelising — paperwork runs during design. Handling it afterwards adds dead months to the programme.

Who actually handles it?

In the classic set-up, the client sits alone between their architect, their managing agent and the case officer. As a general contractor, these steps are part of our scope: we identify the applicable formality at the first visit, assemble the file, engage with the heritage architect where consulted, prepare the resolution put to the general meeting, and build those periods into the contractual programme — exactly as we do for the coordination of all the trades.

One note of caution: this guide gives bearings, not legal advice. The applicable rule depends on the local plan, the exact heritage perimeter and the configuration of the property. Verification is done case by case — it is the first thing we do on any apartment renovation in Paris.

Three frequent questions.

Do you need a permit to renovate the inside of a Paris apartment?

If the works stay internal, do not alter the external appearance, create no floor area and do not change the designated use category, no planning formality is required. Co-ownership consent is still needed as soon as the works touch common parts — load-bearing walls, risers, service ducts — or the external appearance of the building.

Prior declaration or planning permit: how do you decide?

A prior declaration covers works altering the external appearance without creating significant floor area, and the creation of 5 to 20 m² of floor area — raised to 40 m² in urban zones covered by a local plan. Beyond that, or when a change of designated use also modifies the load-bearing structure or the façade, a planning permit is required. An architect becomes mandatory once total floor area exceeds 150 m² after the works.

How long do Paris permits take?

Allow one month of review for a prior declaration, two months for a permit on a single-family house and three months in other cases — each extended by one month where the heritage architect is consulted, which is common in Paris. Add the two-month third-party appeal window from the on-site notice, and the wait for the next general meeting in a co-owned building.

The best time to deal with paperwork is before it becomes a problem: describe your project and we will tell you within 48 hours which formalities apply and what they mean for the schedule.