The European Commission on Thursday stripped the new Athens International Airport (AIA) of 12.8 million euros ($15.85 million) in aid after it violated some of the bloc's rules.
"The Commission has decided to reduce its contribution to the so-called Spata airport ... because of irregularities which have been identified following various audits," Commission spokeswoman Franciose Le Bail told a news briefing.
European Union aid for the project was to total 250 million euros.
The airport, which started operating in March 2001, is owned 55 percent by Greece and 39.8 percent by German construction group Hochtief.
The Commission said the irregularities included requests for excessive funding for certain elements of the project.
The airport also failed to put up obligatory billboards and commemorative plagues to show the EU contributed to building it.
The aid came from EU regional funds, which finance development of poor areas in the 25-member bloc. Those funds amount to about one-third of the bloc's budget, worth 106 billion euros this year.