Building Setback Non-Compliant with Planning Permission Site Plan in Nice

TOPOGRAPHY — SITE LAYOUT

You’ve received your neighbour’s planning permission site plan. You grab your tape measure and check from your boundary fence. The foundation wall already looks 30 centimetres closer than what’s shown on paper. In Nice, 1 in 20 planning permits shows a setback discrepancy detectable by a building surveyor. Your doubt is legitimate.

What you’re seeing — and what it’s really hiding

The symptom is simple: a wall that isn’t where it should be. You’re comparing a tape-measure reading with a dimension on a 1:200 scale plan. What nobody tells you: that plan is a theoretical representation, based on coordinates in the RGF93/Lambert 93 system. Your fence, on the other hand, may have shifted over time, or may never have been accurately staked out in the first place.

Field experience regularly reveals a 42 cm discrepancy between a villa’s actual footprint and its planning permit. The developer had nonetheless « respected » their own staking-out. The problem? The initial staking-out, chained off by the contractor, was itself offset by 35 cm from the legal boundary survey coordinates. In practice, what does that mean? You end up fighting a ghost: the error lies upstream, in how the plan’s points were physically marked out on site.

Theoretical property boundary (survey) Permitted building 5.00 m Building as constructed 4.50 m Measured discrepancy: 0.50 m Technical tolerance, topographic survey (±0.05 m) Discrepancy found 0.50 m Legal threshold Art. L462-1 French Planning Code

The calculation that tips the case

Frankly, everything hinges on a margin-of-error formula. We’re not comparing two measurements, but two uncertainties. On one side, the building’s legal position (permit coordinates). On the other, its actual position (measured with a total station). The maximum admissible discrepancy? It must be less than the square root of the sum of the squares of each survey’s uncertainty. The formula: RMSE = √(σ₁² + σ₂²). σ₁ is the uncertainty of the permit plan (estimated at ±0.10 m for a standard plan). σ₂ is the uncertainty of my control survey using a Leica TS16 total station (±0.02 m).

Admissible RMSE = √(0.10² + 0.02²) = √(0.01 + 0.0004) = √0.0104 ≈ 0.102 m.
In practical terms, in Nice, a discrepancy of more than 10 centimetres between the theoretical and actual position is technically significant. Say I measure, as in the diagram, an actual distance of 4.50 m from the boundary, against a permitted distance of 5.00 m. The discrepancy Δ = 0.50 m. What that means: 0.50 m > 0.102 m. The discrepancy is 5 times greater than the technical tolerance. The building is out of tolerance. This is no longer a tape-measure argument — it’s geometric proof.

Letting it slide is a five-year gamble

Within 6 months, nothing visible happens. The neighbour finishes the works. You’re left with a sense of injustice, but no material damage.

By year 2, the problems surface. Your property in Nice loses value. Your right to a view or to sunlight is affected. For a villa, a missing 50 cm setback can mean 5% less at resale. Worse, if their wall encroaches on your foundation footing, tensile cracks can appear in your own building. The costs? A joint expert survey to establish the encroachment costs between €1,500 and €2,500. Legal action at the Nice court to have the setback corrected? Budget €15,000 to €30,000 in fees, with no guarantee of winning if you don’t have solid expert evidence from the outset. What I see time and again: owners wait until the works are finished. That’s a mistake. By that stage, partial demolition is almost impossible to obtain. You’ll be limited to damages, far below the value lost.

Remedies and guarantees: what you can demand

Your leverage is Article L462-1 of the French Planning Code, paragraph 2, which requires strict compliance with the approved plans. As soon as you identify the discrepancy, send a registered letter with acknowledgement of receipt to the Mayor of Nice (planning department) and to the builder, giving formal notice to suspend the works and carry out a joint topographic survey. Insist on the presence of an independent building surveyor. If they refuse, apply to the Nice judicial court for interim relief to have an expert appointed. Don’t take the builder’s word for it. Only a survey carried out with a total station or GNSS RTK, using coordinates in the NGF-IGN69 system, holds up as evidence. The goal: get the setback corrected before the shell of the building is complete. It’s the only way to fully protect your rights.

Frequently Asked Questions

What discrepancy threshold is considered non-compliant in Nice?

In Nice, a discrepancy of more than 10 cm between the building’s actual position and its planning permit position is technically significant. This tolerance is calculated from the measurement uncertainties (plan and topographic survey). Beyond that, the building is considered out of tolerance.

What should I do if my neighbour’s building crosses the property boundary?

Bring in a building surveyor for a control survey using a total station. If the discrepancy exceeds 10 cm, you can pursue demolition or a reduction in height. Keep all the evidence (photos, plans) and consult a lawyer specialising in planning law.

How much does a setback control survey by a surveyor cost in Nice?

The cost of a control survey by a building surveyor in Nice ranges from €300 to €800 depending on the site’s complexity and size. This includes the technical report detailing the discrepancies measured, which can be used as evidence in court.

How do I know if my neighbour is complying with their planning permission site plan?

You can measure it yourself with a tape measure, but this method is imprecise. The only reliable way is to bring in a surveyor who will use a total station and RGF93/Lambert 93 coordinates to compare the building’s actual position with the one shown on the permit.

What are the risks of leaving a setback discrepancy unaddressed?

In the short term, nothing visible happens. But by year 2, your property can lose value and you risk easement issues. By year 5, the five-year statute of limitations can make any action impossible. It’s crucial to act as soon as the discrepancy is detected.

📅 Updated on 05/08/2026 — By Cassini Expertise, independent building expert covering the 06 & 83 departments. Free quote: 04 22 46 06 04.

📅 Mis à jour le 26/09/2026 — Cassini Expertise, expert bâtiment indépendant (06·83·13·40).