Yes, for indoor use, within a precise framework, which this page sets out in full.
It is the first question asked by professionals, operators of premises open to the public, local authorities and the most demanding homeowners. It deserves better than a sales-pitch “yes”: here is the applicable framework, provision by provision, and how we built the product around it.
This page draws on work carried out with lawyers specialising in new technologies. Checked in September 2026.
Most misunderstandings on this subject stem from the same mistake: confusing two levels that have neither the same author nor the same scope.
It defines what is permitted and what is prohibited. It applies to everyone, and any breach is penalised.
They serve to classify products into technical categories: sirens, alarms, security devices. A standard states the conditions under which a product may bear a given name and serve a given purpose. It does not say what is legal.
This distinction is the key to everything that follows, and in particular to the famous 115-decibel ceiling so many people have heard of.
Inside a closed private or business building, the situation is clear: no French law or regulation known to date sets a decibel ceiling for an acoustic deterrent device used indoors. Used indoors, an acoustic deterrent device is not subject to any specific regulation, and is therefore permitted.
French legal constraints mainly concern outdoor sound devices, which may be regulated by municipal by-laws intended to prevent noise nuisance for neighbours. These restrictions do not apply to indoor use, provided the sound does not spread excessively into public space. On this point, tests show that the sound remains very largely contained within the protected area: outside, neighbours hear at most the equivalent of an alarm siren slightly louder than average.
From technical standards, not from the law. The standards that apply to alarm sirens set a ceiling of 115 dB, above which a device can no longer be classed as a siren within the meaning of those standards. In other words, exceeding this threshold is not prohibited, but the product then no longer belongs to the category of traditional alarm sirens.
This is precisely the case with LIMA SHIELD. It is not a siren: it belongs to another category, that of acoustic deterrent devices, whose purpose is not to alert those nearby but to make an intrusion immediately unbearable through sound saturation. This difference in classification, not a legal grey area, is what makes it possible to use high levels indoors, within a controlled framework.
In the event of a clearly established intrusion, the temporary activation of an acoustic deterrent system falls within the framework laid down by article 122-5 of the French Code pénal on self-defence. This framework requires the attack to be real, current and unjustified, and the response to be necessary, simultaneous and proportionate. The product was designed around these conditions.
| What the legal framework requires | What the system does, by design |
|---|---|
| A necessary response, to a real and current threat. | Automatic triggering only occurs after an intrusion has been confirmed, preceded by warning beeps. |
| A simultaneous response, during the threat, not after. | Emission in sequence, alternating sound and pauses, automatic shut-off, immediate deactivation possible by code, badge or app. |
| A proportionate response to the threat. | Adjustable intensity, aimed at the area to be protected, no physical harm sought, the intruder always has a way out. |
Its use must never be intended to cause physical harm to anyone, only to stop a threat in progress. That is exactly the product's doctrine: deter and make the intruder flee, without physically harming the person. This is not a messaging detail; it is the heart of the design.
Placing such a device on the market is subject to strict European requirements. LIMA SHIELD is CE compliant, among the strictest standards in the world, and each unit is traceable by a unique serial number.
| Area | Reference |
|---|---|
| Radio equipment | RED Directive 2014/53/EU |
| Electromagnetic compatibility | EMC Directive 2014/30/EU, standards EN 301 489-1 and EN 301 489-17 |
| Electrical safety (low voltage) | LVD Directive 2014/35/EU, standard EN 62368-1 |
| Hazardous substances | RoHS II 2011/65/EU |
| Acoustic measurements | EN 61672-1 (class 2), EN 50332-2 |
| Human exposure to noise | Directive 2003/10/EC |
| General product safety | Directive 2001/95/EC |
On top of these come the laws governing use in specific contexts: the French Environmental Code for devices likely to cause significant noise nuisance, the Public Health Code for premises open to the public, and the Labour Code for employees' exposure to noise. We studied each of these frameworks during design, and they are the reason for the delay and the automatic shut-off.
LIMA SHIELD has no camera. Its detection relies on infrared and thermal analysis: it senses heat and movement, never faces. No image is captured or stored, which greatly simplifies compliance with the GDPR and CNIL rules, particularly in places where video surveillance is impossible or unwelcome. The device's communications are encrypted, and the entire product has undergone a cybersecurity audit.
Innovating in security means moving onto ground that the law did not anticipate. We are fully aware of this, and we chose the slowest and safest path.
LIMA SHIELD is designed to deter, not to injure. Its use is regulated, limited and designed above all to protect people.
An honest account of the legal framework also means saying what the product is not, and what it will not do.
Finally, something obvious that deserves to be written down: responsibility for use lies with the user. What could be penalised is not the device but misuse outside the framework described on this page. The installation and configuration rules we provide are there to ensure this situation never arises.
Yes. In France and in the European Union, a private individual may install this type of device at home, provided the product is CE compliant and used as an acoustic deterrent device indoors. What could be penalised is not the device but misuse: deliberate noise nuisance, triggering without cause, deliberate exposure of third parties.
Yes, for indoor use and under the conditions described above. Operators of premises open to the public (ERP) are among the first to ask, and it is for them that the 10-second delay, the warning beeps and the automatic shut-off exist: they let you protect the site while staff and the public are present.
The French Labour Code regulates employees' exposure to noise, and the device was designed with this framework in mind. The system is armed when the site closes, the warning beeps and the delay leave time to deactivate it on arrival, and it is installed facing the areas to be protected rather than workstations. In practice, a brief accidental activation causes at most temporary discomfort, with no substance released and nothing to clean up.
Tests show that the sound remains very largely contained within the protected area. From outside, neighbours hear at most the equivalent of an alarm siren slightly louder than average. Noise nuisance rules may vary from one municipality to another when the emission is audible from outside: where a site has particular constraints, this is addressed when planning the installation.
For sirens installed outdoors, regulations aim to limit nuisance in public space, with rules on power and emission duration. For indoor use, no French law or regulation known to date sets a decibel ceiling for an acoustic deterrent device. The often-quoted 115 dB limit comes from the technical standards for alarm sirens, not from the law, and LIMA SHIELD does not fall within that category of standards.
Yes, and several town halls and municipal police forces are among our earliest enquiries. The system is a capital investment, with no subscription or recurring running costs. A security expert can provide the technical information and the installation plan needed for a public tender.
Every site has its own configuration: presence of the public, adjoining properties, staff, status of the building. A demonstration with a security expert is the quickest way to get a precise answer, and the complete technical file can be sent to you for your insurer or your legal department.
Order LIMA SHIELDcheck availability Request a demonstrationwith a security expertThis page presents the framework applicable in France as of its last update. It does not constitute personalised legal advice.