Six men have been jailed by a German court for their part in a €300m ($391m) scam in the European market for emissions trading.
The six were caged for as long as seven years 10 months for the so-called "carousel fraud”, in which carbon certificates are shuffled around the EU with the aim of pocketing value-added tax on the transactions.
The judge in Frankfurt said the fraudsters had bought the European emissions trading market into disrepute and that Deutsche Bank, which was involved in some of the trades, should have realised what they were up to.
Carousel fraud emerged as a serious problem in Europe’s carbon market in 2009, prompting the UK, France and the Netherlands to change the rules regarding transactions. Germany followed later.
Seven people are due to go on trial in the UK later this year over an alleged £38m carbon trading racket.
The European Commission has set up a special team of "cyber firefighters" in a bid to prevent fraud in the EU Emissions Trading Scheme.