European Court of Justice where judges rule on EU laws
6 September 2013 Last updated at 10:32 BST
The European Court of Justice in Luxembourg is made up of judges from its member states who take on 600 cases a year looking at how laws are interpreted across the EU.
Ranking of judgements show the UK fares less well than "squeaky clean" Slovenia, but is "not as naughty" as France.
Adam Fleming explains it should not be confused with the European Court of Human Rights, which does a different job in a different city.
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