The French Foreign Ministry warned the United States on Tuesday that Europe would "consider the implications" of the Pentagon's alleged decision to favour US firm Boeing over European consortium EADS in its tender for the contract to replace the US Air Force's 1950s-era refuelling jets.
The deal is worth 26 million euros and pitched EADS and its US partner Northrop Grumann against Boeing.
However, the Europe-led consortium was forced to pull out after the Pentagon changed its criteria at the last minute.
EADS and Northrop Grumann claim that the requirements for the programme were unfairly weighted in favour of their US rival.
In Brussels, EU trade chiefs have issued a statement querying the terms of the tender, and a German government minister accused the United States of protectionism, threatening to ask the World Trade Organisation to look into the affair.
The Northrop-EADS team had originally won the contract in February 2008, but the deal was cancelled after Boeing successfully appealed the decision to the US Congress.
"We have no chance of winning the competition and we regret it," said EADS chief executive Louis Gallois, "because we think that we have the better plane."