Last checked: August 2026.
France is the clearest case in Europe, and not in the direction most people expect. The French government's own published position is that magnet fishing without prior State authorisation is illegal.
Answering a written question in the Senate in February 2021, the Ministere de la Culture stated:
"Presentee le plus souvent comme une activite benevole visant a permettre la depollution des cours d'eau, cette pratique est en realite illegale a defaut d'obtenir une autorisation prealable de l'Etat."
(Most often presented as a voluntary activity aimed at cleaning up waterways, this practice is in reality illegal in the absence of prior State authorisation.)
The question had been asked precisely because "de nombreuses differences de traitement apparaissent selon les prefectures" — treatment varies between prefectures. The answer was that the requirement is national.
Why: the metal-detector law captures magnets
Article L. 542-1 of the Code du patrimoine provides that "nul ne peut utiliser du materiel permettant la detection d'objets metalliques, a l'effet de recherches de monuments et d'objets pouvant interesser la prehistoire, l'histoire, l'art ou l'archeologie, sans avoir, au prealable, obtenu une autorisation administrative".
Note the wording: materiel permettant la detection d'objets metalliques — equipment allowing the detection of metal objects. It is not limited to electronic devices, and the only exclusion in the surrounding framework is a camera.
Prefectures read this as covering magnets. The Prefecture de la Vienne puts it in the strongest terms found anywhere:
"Quelle que soit l'intention, l'utilisation d'un detecteur ou d'un aimant pour le milieu subaquatique est consideree comme une recherche ou une prospection de vestiges ou de mobilier archeologiques."
(Whatever the intention, the use of a detector or a magnet in the underwater environment is considered a search or prospection for archaeological remains or artefacts.)
The same page states that recreational or clean-up magnet fishing "est illegale" and that authorisations "ne sont delivrees que dans le cadre de recherches scientifiques" — only for scientific research.
The government has refused to create a hobby exemption
This was tested again in 2024. Asked to distinguish archaeological detection from recreational searching, the Ministere de la Culture replied that such a change "n'est pas envisageable" — not under consideration.
Departements with confirmed prohibitions
On top of the national requirement, a number of prefectures have issued arretes banning the practice outright. Confirmed from official sources:
- Somme (80) — arrete of 5 August 2019
- Charente-Maritime (17) — arrete n° 22EB1014 of 3 January 2023
- Loir-et-Cher (41) — total ban across all watercourses, lakes, canals and rivers in the departement
- Loiret (45) — total ban, arrete of 26 November 2021
- Marne (51) — all waters in every commune of the arrondissement de Reims, plus listed communes elsewhere
- Moselle (57) — total ban in all watercourses, arrete of 31 May 2021
Others including Vienne, Loire-Atlantique, Vendee, Mayenne, Ardennes and Indre publish official notices restating the authorisation requirement without a standalone ban. Mayenne requires three separate authorisations — landowner, DRAC, and a water-law declaration.
A warning about lists you may find elsewhere. Several hobby sites publish "banned departement" lists that are widely copied. Checking them against prefecture sources, at least three entries are contradicted by the prefecture's own page, and one entry is a region rather than a departement. Arretes are also sometimes time-limited and renewed, so any list is a snapshot. Check the prefecture directly.
Penalties
- Using detection equipment without authorisation — contravention de 5e classe, 1 500 EUR, reported as 3 000 EUR on repeat, with possible confiscation of equipment
- Failing to declare a chance archaeological find — a delit, 3 750 EUR
- Unauthorised excavation — 7 500 EUR
What happens to what you find
Article L. 531-14 requires the discoverer and the landowner to declare a chance find immediately to the maire, who passes it to the prefet. The Ministry has stated this obligation applies "quelles qu'aient ete les modalites de la decouverte" — however the object was found.
For movable archaeological property, the ordinary French treasure-trove rule does not apply. Such objects are presumed to belong to the State. The Ministry also invokes the Edit de Colbert, which attributes to the State any discovery made in watercourses.
Ordnance
France has significant unexploded ordnance in former battlefield regions and along the western coast. The Groupement d'Intervention du Deminage, part of the Interior Ministry, collects and destroys over 500 tonnes of explosive devices a year.
The standard official instruction: do not touch it, establish a perimeter, mark the location, warn others, notify the mairie, gendarmerie or police, and stay discreet to avoid drawing onlookers. The Prefecture de la Vendee adds a point worth noting — "En cas d'accident, votre responsabilite pourrait etre engagee".
Waterways
One honest gap: we found no Voies Navigables de France policy on magnet fishing either way. VNF has acknowledged it as a source of damage to submerged cables, but publishes no prohibition or authorisation requirement we could locate. The authorisation route the government points to is the prefecture, not VNF.
Before you go
- Contact the prefecture of the departement. This is the body the government names.
- Check whether a local arrete bans the practice where you are.
- For the heritage authorisation, the route is the DRAC / Service regional de l'archeologie, granted by arrete du prefet de region.
- Assume you must declare anything that looks archaeological.
This article is general information about published rules, not legal advice, and it is not a statement of what will or will not happen to you. Prefectural arretes vary and are amended. Always confirm the current position with the prefecture responsible for the water you plan to fish, and seek qualified legal advice if anything material turns on it.
