"The decision was made. We see no grounds to reconsider," commission spokeswoman Dana Spinant said.

The French government on Thursday asked the commission to rethink the hiring of US economics expert Fiona Scott Morton to such a sensitive position, saying it raised conflict-of-interest risks.

Scott Morton, a Yale University economics professor and former lobbyist, served as deputy assistant attorney general for economics at the US Department of Justice's antitrust division in 2011 and 2012. There, she was in charge of economists who investigated mergers.

She has also worked as a consultant for Amazon, Apple and Microsoft.

The EU executive announced that she had been chosen to serve from September as the new chief economist at the commission's antitrust unit, which comes under EU antitrust supremo Margrethe Vestager.

The unit is charged with making sure EU markets remain competitive -- including ensuring that US tech titans do not abuse their market dominance, which has already seen them served record fines.

French government ministers on Thursday came out against the appointment, as did some lawmakers in the European Parliament.

"This appointment deserves to be reconsidered by the commission," French Foreign Minister Catherine Colonna tweeted.

French Digital Minister Jean-Noel Barrot said Scott Morton's hire "raised legitimate questions" as Europe embarks on digital regulation.

- 'Reverse the decision' -

The leaders of four parliamentary groupings in the European Parliament, ranging from the left to the centre-right, said in a letter addressed to Vestager "we fail to understand the consideration of non-EU candidates for such a high-ranking and strategic position".

The groups said they opposed the appointment and asked the commission "to reverse the decision".

On Friday evening, France's largest employer federation Medef also denounced the selection, calling out Brussels for "contempt for European public opinion".

But Spinant, the commission spokeswoman, said the EU commissioners "endorsed the proposal to appoint this person (Scott Morton) to the position" and it was viewed as a settled matter.

Commission chief Ursula von der Leyen, a former German defence minister, has fostered close relations with Washington since the administration of President Joe Biden succeeded that of Donald Trump, whose volatile behaviour unsettled Europe.

The current term of the European Commission ends late next year.

Von der Leyen has not said whether she intends to try for a second mandate, but if she does she would need support from key member states including France.