The EU's taking Ireland to court - in a row over the fuel used for private yachts.
The European Commission is taking action because Irish law allows yacht owners to use the same cheaper fuels that are intended for commercial vehicles - usually known as the cheaper, 'green' diesel.
Brussels says this can't be allowed, because it undermines the savings that commercial operators are supposed to gain by being allowed to use cheaper fuels.
Ireland's law also means Irish sailors could also be fined in other countries, if they're using cheaper fuels than those countries allow.
The authorities say Ireland has ignored letters sent earlier this year, warning about the problem.
The case will now be heard at the General Court of the EU, but isn't likely to be heard in court until 2016.
