Authorities swooped across Europe on Friday, making 26 arrests in connection with what they describe as an organised criminal network trading in illegal horse-meat.
Police and judicial authorities from France, Belgium, Germany, Ireland, Luxembourg, the Netherlands and Britain were involved in the operation.
In addition to the arrests, €37,000 in cash and more than 800 horse passports were seized, as well as medication, dozens of microchips and computer equipment.
More than 200 horses will be examined by veterinary services, authorities said.
Dozens of searches of commercial and private premises were carried out during the operation, which was coordinated by Eurojust, the European Union’s judicial cooperation unit. The operation was led by Eurojust’s French Desk.
French authorities estimate that, between 2010 and 2013, 4700 horses unfit for human consumption were slaughtered and introduced into the legal food chain.
Four hundred horse passports with anomalies were detected in France alone, Eurojust said.
It alleged that falsification, suppression and/or modification of official health documentation by the group allowed horse-meat deemed unfit for human consumption to fraudulently enter the European food chain.
EU regulations require that all meat sold for human consumption must be accounted for and traceable.
Investigations into the main suspect, a Belgian national operating in Belgium, began in November 2012. It was led by an investigating judge from the Tribunal de Première Instance of the Province of Luxembourg, Belgium.
France started its investigation in July 2013, led by an investigating judge from the Tribunal de Grande Instance of Marseille.
The investigations revealed links to the activities of an organised criminal group in other EU states, such as Ireland and the Netherlands.
As a result of information received from Belgium and France, police in Kent started an investigation in Britain.
Eurojust provided the opportunity for affected member states to discuss the most efficient common judicial strategy and response.
Two coordination meetings were organised by Eurojust and held this year. It provided analytical support throughout the investigation.
A joint investigation team was formed between France and Belgium in May 2014, with funding from Eurojust. Latest developments in the case led to the team being extended to Britain this month.