The European Union’s Judicial Cooperation Unit (Eurojust) reported that it had stopped an organised criminal network involved in the trade in illegal horsemeat, resulting in the seizure of 800 horse passports and €37,000 in cash.
Police and judicial authorities from France, Belgium, Germany, Ireland, Luxembourg, the Netherlands and the UK were involved in the co-ordinated "common action day" investigation.
The investigation was centred in France, the Netherlands and Belgium, and "dozens of searches of commercial and private premises were carried out".
Eurojust reported that 4,700 horses unfit for human consumption were slaughtered and introduced into the legal food chain between 2010-2013. The unit said 400 horse passports with "anomalies" were found in France alone.
Meanwhile, an investigation into the main suspect began in 2012, which revealed links to Ireland and the UK.
The prosecution of a Dutch meat wholesaler, the first related to the horsemeat scandal, was delivered earlier this month. Willy Selten, 45 was sentenced to two-and-a-half-years for selling over 300 tonnes of horsemeat on as beef.
Eurojust said the investigation was ongoing.