Legal metrology, a little-known but fundamental branch of law in our economy, governs all measuring instruments used in commercial transactions, public health or personal safety. These complex and technical regulations have a simple aim: to guarantee the accuracy and reliability of measurements in order to protect consumers and ensure fair trading. Every day, millions of transactions are based on weighing, counting or various other measurements. Understanding this legal framework is essential for any professional using measuring instruments.
The foundations of legal metrology law
French and European legal framework
Legal metrology law is based on an ancient foundation, which has been modernised in line with technological developments and European harmonisation. In France, the law of 4 July 1837 on weights and measures was the foundation stone of this regulatory edifice, imposing the use of the decimal metric system.
Today, decree no. 2001-387 of 3 May 2001 on the inspection of measuring instruments is the central text of the national system. It defines the categories of instruments subject to inspection and the various mandatory verification operations. It is supplemented by a number of decrees specific to each category of instrument.
At European level, several directives govern this field, notably Directive 2004/22/EC on measuring instruments (MID) and Directive 2009/23/EC on non-automatic weighing instruments. These directives, which have been transposed into French law, aim to harmonise technical requirements and conformity assessment procedures across the European Union, thereby facilitating the free movement of measuring instruments.
Legal units of measurement
The International System of Units (SI), adopted by the General Conference on Weights and Measures, is the compulsory reference in France. This system comprises seven basic units: the metre (length), the kilogram (mass), the second (time), the ampere (electric current), the kelvin (temperature), the mole (quantity of matter) and the candela (luminous intensity).
The use of units other than legal units is prohibited in the fields of economics, health, public safety and administrative operations, unless specific derogations are granted. For example, a trader cannot legally sell his products by the yard or the pound, but must use the metre or the kilogram.
This standardisation of measurement units is fundamental to ensuring mutual understanding and comparability of measurements. It is the foundation on which the entire regulation of units of measurement in FranceFailure to do so may result in penalties.
The main obligations for professionals
Compliance of instruments with legal units
Any professional using regulated measuring instruments must ensure that they comply with the legal units and technical requirements defined in the texts. This obligation applies not only to manufacturers, importers and distributors of instruments, but also to their users.
Article 12 of the Decree of 3 May 1961 prohibits the sale, delivery, display or use of measuring instruments that do not comply with the regulations, in particular those bearing inscriptions or graduations other than those resulting from the use of legal units.
In practice, this means that instruments marketed and used in France must be marked in units of the international system or in units authorised by derogation. For example, a fever thermometer must be graduated in degrees Celsius and not in degrees Fahrenheit.
Compliance with control procedures
As well as complying with the legal units, professionals must submit their instruments to the various checks required by the regulations. These checks vary according to the category of instrument, but generally follow a common pattern:
- Type examination (or model approval): validation of the instrument's design
- Initial inspection: inspection of new or repaired instruments
- Checking the installation: checking the installation conditions
- In-service inspections: periodic checks and monitoring
Instrument owners are required to have these inspections carried out at the times stipulated in the regulations and to keep the corresponding documentation up to date. Failure to comply with these obligations may result in administrative or criminal penalties significant.
These control procedures are essential to ensure that instruments maintain their metrological qualities throughout their use, as detailed in our analysis of procedures for checking measuring instruments.
Checking measuring instruments
Overview of the different control operations
Metrological inspection involves a number of complementary operations at different stages in the life of the instrument:
Type examination is the first stage in the inspection process. It involves validating the design of the instrument, leading to the issue of a certificate attesting that the type meets the regulatory requirements. This certificate is generally valid for a renewable period of ten years.
Initial verification is then carried out on new or repaired instruments. It may take the form of a unit inspection or surveillance of the manufacturer's or repairer's quality assurance system. Compliant instruments receive an initial verification mark.
For some instruments, it is also compulsory to check the installation. This operation ensures that the installation conditions guarantee correct use in compliance with regulatory requirements.
Lastly, in-service inspections include various operations: periodic inspection, periodic revision or self-monitoring by the owner. Periodic inspection, carried out at regular intervals defined by decree, is the most common operation. It results in the affixing of an inspection mark valid until the next due date.
The competent bodies
Metrological control involves a number of different players, both public and private:
At central level, the Bureau de la Métrologie (Metrology Office), attached to the Ministry of Industry, draws up the regulations and coordinates the national inspection system.
The Laboratoire national de métrologie et d'essais (LNE) plays a major technical role, particularly in type testing and the approval of quality assurance systems.
At regional level, the Directions régionales des entreprises, de la concurrence, de la consommation, du travail et de l'emploi (DIRECCTE) monitor the market and carry out certain checks.
Finally, organisations appointed by the Minister for Industry or approved by the departmental prefects carry out a large proportion of the inspections, particularly periodic checks.
This multi-player system ensures effective territorial coverage and adaptation to the specific features of each category of instrument.
Regulation by instrument category
Overview of the main regulated categories
Metrological regulations cover a wide range of instruments, grouped into categories according to their function and field of use:
Weighing instruments are a fundamental category, with a distinction between non-automatic instruments (commercial scales, medical scales) and automatic instruments (checkweighers, weighfeeders). They are subject to particularly strict regulations, given their importance in commercial transactions.
Instruments for measuring volumes and flows include water meters, fuel dispensers and measuring containers. These instruments are subject to regular checks because of their direct economic impact on consumers.
Instruments for measuring time and speed include taximeters and tachographs, which are essential for billing taxi fares and enforcing driving times in the transport sector.
In the energy sector, electricity, gas and heat meters are subject to specific checks, adapted to their technical characteristics and economic stakes.
Finally, more specialised instruments are also regulated, such as breathalysers, exhaust gas analysers and medical thermometers, which meet public health or environmental protection requirements.
Sector specificities
Each category of instrument is subject to particular requirements, adapted to its specific technical features and context of use, as shown by our study of the specific regulations for instruments by category.
In the commercial sector, scales must undergo periodic annual verification, and retailers are required to display the unit price of many pre-packaged products.
In the case of energy-related instruments, the meters must guarantee lasting accuracy, with checks adapted to their technology. Smart meters, which are developing rapidly, are subject to specific data security requirements.
In the healthcare sector, instruments such as fever thermometers and blood pressure monitors have to comply with particularly strict standards of accuracy, given the medical decisions that can be made on the basis of their measurements.
Environmental instruments, such as gas analysers or sound level meters, are regulated according to the pollution or nuisance standards they are used to monitor.
This regulatory diversity reflects the multiplicity of uses and the varying importance of instruments in different sectors, while maintaining a common principle: guaranteeing the reliability of measurements to protect economic players and consumers.
Risks and penalties in the event of non-compliance
The different types of penalty
Failure to comply with metrological regulations can result in various types of penalty, proportionate to the seriousness of the breaches observed:
Administrative penalties include the suspension of initial verification and the placing on the market of instruments of a given model, or an order to bring defective instruments into conformity. The authorities may also order the seizure and confiscation of non-compliant instruments.
On the criminal front, article 43 of the decree of 3 May 2001 provides for a third-class fine (450 euros maximum) for various offences: use of instruments in non-compliant conditions, commissioning without prior verification, etc.
More severe penalties are provided for when the use of non-compliant instruments is accompanied by deception about the quantity of goods sold. Article L. 213-1 of the French Consumer Code punishes this practice with two years' imprisonment and a fine of €37,500, penalties that are doubled when the deception is committed using false or inaccurate instruments.
Consequences for companies
In addition to administrative and criminal penalties, non-compliance with metrological requirements can have a number of negative consequences for companies:
In economic terms, the use of defective instruments can lead to direct financial losses, through under- or over-estimation of the quantities sold or purchased. It can also give rise to claims for damages from injured customers.
The company's image can be seriously affected, particularly if media coverage of a case of deception linked to the use of non-compliant instruments. Customer confidence, which is essential to commercial relations, may be permanently damaged.
In operational terms, forced compliance can lead to significant costs and business disruption, particularly when it involves replacing instruments or modifying established processes.
Lastly, certain administrative sanctions may directly affect the business, such as a temporary ban on using certain instruments, or even closure of the establishment in the most serious cases.
Faced with these risks, companies have every interest in ensuring the compliance of their measuring instruments and using advice from lawyers specialising in legal metrology to implement an appropriate prevention strategy.
Do you need legal advice on legal metrology? Our firm is at your disposal.
Frequently asked questions
Which measuring instruments are subject to metrological control?
Instruments used in commercial transactions, health, safety, tax operations and to determine advertised or imposed characteristics.
What is the difference between an initial inspection and a periodic inspection?
Initial verification concerns new or repaired instruments, while periodic verification applies to instruments in service at regular intervals.
What are the penalties for using a non-compliant measuring instrument?
A fine for a 3rd class offence (€450), and up to 2 years' imprisonment and a €37,500 fine for misleading consumers as to quantity.
Who is authorised to carry out metrological controls in France?
Bodies designated by the Minister for Industry, bodies approved by the prefects and, in their absence, the DIRECCTE.
How often should I have my measuring instruments checked?
The frequency varies according to the category of instrument: annual for commercial scales, biennial for certain water meters, etc.
How do I know if a measuring instrument complies with legal requirements?
The instrument must bear the regulatory marking (valid type examination mark and verification mark).
What regulations apply to water and electricity meters?
Water meters are governed by decree no. 76-130 and the order of 6 March 2007, while electricity meters are governed by an amended decree of 1935.
What are a retailer's obligations when it comes to weighing scales?
Use scales that conform to the approved type, subject them to annual periodic inspection and maintain their accuracy.
Does the MID (Measuring Instruments Directive) apply in France?
Yes, it has been transposed by decree no. 2006-447 of 12 April 2006, and concerns many categories of measuring instruments.
Can you repair a regulated measuring instrument yourself?
No, repairs must be carried out by professionals who will affix their identification mark and submit the instrument to a new check.
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