The State agency responsible for the Luas has been ordered to put up new signs in Irish as well as English, despite concerns they could make driving conditions less safe.
The Railway Procurement Agency has been ordered to replace the signs, in response to a complaint that they were written in English only.
The Irish Language Commissioner ordered the notices, which remind drivers to check their route as well as telling them where to park, be supplied in two languages.
The decision was reached despite the company's concerns about a clutter effect for drivers.