PROPERTY LAW — ENCROACHMENT

You’ve just received a registered letter. Your neighbour in Antibes claims your new fence encroaches 15 centimetres onto their land. You’re stunned. You grab a tape measure and check from the corner of the shared wall. Result: 0 cm of encroachment — the fence sits exactly on the boundary. So who’s right? In 9 cases out of 10, both tape-measure readings are wrong. The truth lies underground, buried in the official boundary survey, and only a contradictory total station survey can reveal it.

What you see — and what it’s really hiding

You see two property owners, a tape measure each, and figures that don’t match. The dispute looks simple. What you don’t see is the real issue: a property boundary isn’t a line drawn on the ground. It’s a series of georeferenced points defined by (X, Y, Z) coordinates in the RGF93/Lambert 93 system. Your corner wall? It may have shifted over time. The ground? It’s rarely perfectly flat. Measuring with a tape from an assumed fixed point is like navigating at sea with a faulty compass: errors compound.

What I regularly find on site, particularly in the old town of Antibes or on sloped plots, is a cumulative effect. A wall that isn’t perfectly straight (+2 cm), sloped ground not compensated for in the measurement (+5 cm), an imprecise tape reading (+1 cm). Total error can easily reach 10 to 20 cm over a 15-metre distance. Frankly, that’s the norm, not the exception. You and your neighbour are probably both measuring from different starting points, or using methods that introduce bias. The correct reference point is the geodetic marker or the notarised boundary point, not your wall corner.

The equation of truth: root mean square error

To settle the matter, we don’t average the two measurements. We calculate the gap between the fence’s actual position and the legal boundary position. The key metric is the Root Mean Square Error (RMSE). It quantifies overall measurement precision by combining every source of uncertainty. The formula is: RMSE = √(σ₁² + σ₂² + … + σₙ²), where σ represents the standard deviation of each error source.

Take a concrete case in Antibes. Suppose the legal boundary is defined by two survey points 20 m apart. I carry out a survey using a Leica TS16 total station (angular precision: 1″, linear precision: ±2 mm + 2 ppm). Sources of error: reference point setup (σ_ref = 0.005 m), sighting on the fence (σ_sight = 0.003 m), thermal drift of the instrument (σ_temp = 0.001 m). RMSE becomes: RMSE = √(0.005² + 0.003² + 0.001²) = √(0.000025 + 0.000009 + 0.000001) = √0.000035 ≈ 0.0059 m, roughly 6 mm.

Now I measure the distance between the fence and the legal boundary. Result: Δ = 0.14 m (14 cm). My measurement uncertainty (RMSE) is 0.006 m. The encroachment is therefore 0.14 m ± 0.006 m. In practical terms: the encroachment is clearly established, since 14 cm far exceeds the 6 mm margin of error. The typical accepted tolerance for this kind of boundary survey is around 2 to 5 cm. Here, we’re well outside that tolerance. Article 545 of the French Civil Code is clear: “No one may be compelled to give up their property, except for reasons of public interest…” An encroachment is an infringement of that property right. Article 555, meanwhile, deals with construction carried out by a third party on another’s land and the compensation owed. Paragraph 1 applies directly here: if the fence is built on the neighbour’s land, even in good faith, the neighbour can demand its removal or claim ownership against compensation.

Let it slide and the bill doubles within 5 years

If you do nothing, hoping “it’ll sort itself out”, you’re setting yourself up for a near-certain escalation. Within 6 months, the dispute sours. Friendly conversations turn into lawyers’ letters. Within 2 years, if the neighbour takes the matter to the Grasse Judicial Court (which has jurisdiction over Antibes), costs pile up: bailiff’s fees for a formal report, court-appointed expert fees (between €2,000 and €5,000), and legal fees.

But the worst part isn’t financial, it’s structural. A fence built on the boundary but encroaching creates a zone of physical conflict. Any foundations can disrupt the natural drainage of the neighbouring plot. In Antibes, with our sometimes clay-heavy soils, this can influence differential settlement. A secondary pathology can then appear: a microcrack in a shared wall caused by asymmetric stress. Five years down the line, you’re no longer dealing with a simple 15 cm issue, but a complex case of potential structural disorders, where liability becomes even harder to establish. The total cost (demolition, rebuilding in the right place, possible repairs) can then easily exceed €10,000, not counting the loss in property value.

Remedies and guarantees: what you can demand

You’re entitled to a reliable, contradictory measurement. The applicable guarantee is that of boundary surveying and strict respect of property limits, based on Articles 545 and 555 of the French Civil Code. Specifically, demand a contradictory topographic survey. Each party appoints their own expert, or you agree on a single joint expert. This expert, equipped with a total station or RTK GNSS, will record the exact position of your fence and compare it against the boundary survey or cadastral data. Their official report will carry legal weight. If encroachment is confirmed, there are two outcomes: either you agree amicably on compensation (value of the occupied land) and relocate the fence, or, in case of disagreement, the survey report serves as solid evidence before the Grasse court. Don’t wait. Send a registered letter with acknowledgement of receipt proposing the appointment of a building/planning expert. It’s the only way to move from dispute to an undeniable figure.

Frequently Asked Questions

My neighbour says my fence encroaches 15 cm, but my tape measure reads 0 cm. Who’s right?

In 9 cases out of 10, both tape-measure readings are wrong. A property boundary isn’t a visible line but a set of georeferenced points. Only a contradictory total station survey, carried out by a building expert, can settle the matter by calculating the actual gap against the official boundary survey.

How much does a contradictory total station survey cost in Antibes?

A contradictory total station survey for a fence dispute in Antibes typically costs between €400 and €800, depending on terrain complexity and the number of points to be surveyed. This generally includes the technical report and travel costs. It’s a far smaller investment than going to court.

What if my neighbour refuses the contradictory survey?

If your neighbour refuses, you can offer to split the cost, or point out that without an objective measurement, the dispute is likely to end up in court. In the meantime, don’t alter the fence. A building expert can also carry out a survey alone to produce a report, but a contradictory survey carries more legal weight.

Why isn’t a tape measure reliable for measuring an encroachment?

A tape measure accumulates errors: a wall that isn’t perfectly straight, sloped ground not compensated for, an imprecise reading. Over 15 metres, total error can reach 10 to 20 cm. The legal boundary is defined by precise coordinates (RGF93/Lambert 93), which only a total station can locate with millimetre accuracy.

How does a contradictory total station survey work?

A building expert comes on site with a total station (e.g. Leica TS16). They set up on the reference points from the notarised boundary survey, then measure the fence’s actual position. Both parties are present. The final report gives the precise gap between the fence and the legal boundary, along with the root mean square error.

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📅 Updated on 27/08/2026 — By Cassini Expertise, independent building expert covering departments 06 & 83. Free quote: 04 22 46 06 04.

PROPERTY — ENCROACHMENT

You bought a house in Antibes, with a sea view, in the Badine district. The boundary plan dates from 1985. Last year, your neighbor replaced the old fence with a stone wall. Since then, you have a doubt: he may have gained 30 cm on your land. You measure with a ruler, you look on Géoportail (French mapping portal), but nothing matches. A bailiff’s report? It only records, not measures precisely. What you need is a contradictory topographical survey with a total station.

What you see — and what it really hides

The wall seems straight, well aligned with the street. But the ground is sloping, the old boundary markers have disappeared. The cadastral plan, at 1/1000 scale, is not precise enough to decide. In a similar case last year, I measured a discrepancy of 18 cm at the back of the plot, invisible to the naked eye. The owner had relied on the paper boundary plan, without accounting for support deformation.

What no one says: a simple laser distance meter is not enough. You need a Leica TS16 total station with an angular accuracy of 1″ and a range of 500 m. Stationed on a known point in Lambert 93 (French projection system), it measures each angle and distance. Coordinate calculation allows superimposing the actual fence onto the vector cadastral plan. Then the encroachment becomes clear.

The calculation that changes everything: root mean square error

The accuracy of a total station survey is calculated by the root mean square error (RMSE): RMSE = √(σ₁² + σ₂²), where σ₁ is the standard deviation of distance measurement (±3 mm for a Leica TS16) and σ₂ that of angular measurement (1″ i.e., about 0.5 mm at 100 m). For a station 30 m from the fence, RMSE = √(3² + 0.5²) ≈ 3.04 mm. In practice, we add the uncertainty of fitting to boundary markers (±5 mm), so total RMSE ≈ 6 mm. An encroachment of 15 cm is therefore 25 times greater than the measurement tolerance. It is indisputable.

Concretely, in Antibes, on a slope of 15%, horizontal projection is essential. The slope is calculated: slope = Δh/L × 100. If the elevation difference between two markers is 1.5 m for a horizontal distance of 10 m, the slope is 15%. The total station directly measures the horizontal distance, avoiding tape errors. The result is unequivocal: the fence encroaches 15 cm onto your land. According to Article 545 of the French Civil Code (paragraph 1: “No one may be compelled to transfer his property, except for public utility…”) and Article 555 (paragraph 2: “The owner of the land may demand the demolition of constructions, plantations, or works…”), you are entitled to demand removal of the encroachment.

What happens if you do nothing

Within 6 months, the wall remains stable. But in 2 years, roots from neighboring hedges could destabilize it, worsening the encroachment. If you sell, the buyer may require regularization, and the price will drop by 10 to 15% for an unresolved encroachment. I saw a case in Juan-les-Pins where a 20 cm encroachment blocked a sale for 8 months, with legal fees of €5,000.

In the long term (5 years), runoff water can infiltrate along the poorly positioned wall, causing a landslide. In the Alpes-Maritimes, swelling clays worsen cracks. Restoration costs can reach €20,000.

Recourse and guarantees: what you can demand

The applicable guarantee is under Articles 545 and 555 of the French Civil Code. You must send a registered letter with acknowledgment of receipt to your neighbor, detailing the encroachment and demanding removal within 30 days. Attach the contradictory measurement report. If refused, petition the Grasse judicial court (summary expertise). A court-appointed expert can order demolition at the neighbor’s expense. Frankly, act quickly: the 30-year prescription runs, but it’s better not to wait.

📅 Updated on 29/08/2026 — By Cassini Expertise, independent building expert serving the Alpes-Maritimes (06) & Var (83). Free quote: 04 22 46 06 04.

Frequently Asked Questions

Can I build a fence on the property line in Antibes?

In general, you can build a fence on your own property, but it must not encroach onto the neighboring land. If the existing fence is already in place, a boundary survey is necessary to determine the exact limits before any construction.

What should I do if my neighbor has built a fence that encroaches on my land in Antibes?

You can request an amicable boundary survey with a licensed surveyor. If the survey reveals an encroachment, you can demand demolition of the encroaching section or compensation. In case of dispute, legal action is possible.

How can a theodolite topographical survey prove a fence encroachment?

A theodolite survey provides precise angle and distance measurements, allowing the exact coordinates of the fence points to be determined. By comparing this data with the property deeds and cadastral plan, it is possible to establish whether the fence exceeds the legal boundaries.

PROPERTY — ENCROACHMENT

You bought a house in Antibes, with a sea view, in the Badine district. The boundary plan dates from 1985. Last year, your neighbor replaced the old fence with a stone wall. Since then, you have a doubt: he may have gained 30 cm on your land. You measure with a ruler, you look on Géoportail (French mapping portal), but nothing matches. A bailiff’s report? It only records, not measures precisely. What you need is a contradictory topographical survey with a total station.

What you see — and what it really hides

The wall seems straight, well aligned with the street. But the ground is sloping, the old boundary markers have disappeared. The cadastral plan, at 1/1000 scale, is not precise enough to decide. In a similar case last year, I measured a discrepancy of 18 cm at the back of the plot, invisible to the naked eye. The owner had relied on the paper boundary plan, without accounting for support deformation.

What no one says: a simple laser distance meter is not enough. You need a Leica TS16 total station with an angular accuracy of 1″ and a range of 500 m. Stationed on a known point in Lambert 93 (French projection system), it measures each angle and distance. Coordinate calculation allows superimposing the actual fence onto the vector cadastral plan. Then the encroachment becomes clear.

The calculation that changes everything: root mean square error

The accuracy of a total station survey is calculated by the root mean square error (RMSE): RMSE = √(σ₁² + σ₂²), where σ₁ is the standard deviation of distance measurement (±3 mm for a Leica TS16) and σ₂ that of angular measurement (1″ i.e., about 0.5 mm at 100 m). For a station 30 m from the fence, RMSE = √(3² + 0.5²) ≈ 3.04 mm. In practice, we add the uncertainty of fitting to boundary markers (±5 mm), so total RMSE ≈ 6 mm. An encroachment of 15 cm is therefore 25 times greater than the measurement tolerance. It is indisputable.

Concretely, in Antibes, on a slope of 15%, horizontal projection is essential. The slope is calculated: slope = Δh/L × 100. If the elevation difference between two markers is 1.5 m for a horizontal distance of 10 m, the slope is 15%. The total station directly measures the horizontal distance, avoiding tape errors. The result is unequivocal: the fence encroaches 15 cm onto your land. According to Article 545 of the French Civil Code (paragraph 1: “No one may be compelled to transfer his property, except for public utility…”) and Article 555 (paragraph 2: “The owner of the land may demand the demolition of constructions, plantations, or works…”), you are entitled to demand removal of the encroachment.

What happens if you do nothing

Within 6 months, the wall remains stable. But in 2 years, roots from neighboring hedges could destabilize it, worsening the encroachment. If you sell, the buyer may require regularization, and the price will drop by 10 to 15% for an unresolved encroachment. I saw a case in Juan-les-Pins where a 20 cm encroachment blocked a sale for 8 months, with legal fees of €5,000.

In the long term (5 years), runoff water can infiltrate along the poorly positioned wall, causing a landslide. In the Alpes-Maritimes, swelling clays worsen cracks. Restoration costs can reach €20,000.

Recourse and guarantees: what you can demand

The applicable guarantee is under Articles 545 and 555 of the French Civil Code. You must send a registered letter with acknowledgment of receipt to your neighbor, detailing the encroachment and demanding removal within 30 days. Attach the contradictory measurement report. If refused, petition the Grasse judicial court (summary expertise). A court-appointed expert can order demolition at the neighbor’s expense. Frankly, act quickly: the 30-year prescription runs, but it’s better not to wait.

📅 Mis à jour le 29/08/2026 — Par Cassini Expertise, expert bâtiment indépendant 06 & 83. Devis gratuit : 04 22 46 06 04.

Questions fréquentes

Puis-je construire une clôture sur la limite de propriété à Antibes ?

En général, vous pouvez construire une clôture sur votre propriété, mais elle ne doit pas empiéter sur le terrain voisin. Si la clôture existante est déjà en place, un bornage est nécessaire pour déterminer les limites exactes avant toute construction.

Que faire si mon voisin a construit une clôture qui empiète sur mon terrain à Antibes ?

Vous pouvez demander un bornage amiable avec un géomètre-expert. Si le bornage révèle un empiètement, vous pouvez exiger la démolition de la partie empiétante ou une indemnisation. En cas de litige, une action en justice est possible.

Comment un levé topographique au théodolite peut-il prouver un empiètement de clôture ?

Un levé au théodolite fournit des mesures précises des angles et des distances, permettant de déterminer les coordonnées exactes des points de la clôture. En comparant ces données avec les titres de propriété et le plan cadastral, on peut établir si la clôture dépasse les limites légales.