France's Socialist premier Manuel Valls admitted in remarks published Sunday to having made "a blunder" by using a government jet to fly to the Champions League final with his two sons.

The popular prime minister has sought to end the controversy by pledging to refund part of the cost of last weekend's junket, despite insisting he was on official business.

"This is a lesson," Valls told the Journal du Dimanche newspaper.

"It was a mistake, a blunder. I gave the impression to the French people that I had not devoted myself to them. I am sorry."

Born in Barcelona and an FC Barcelona fan, Valls said he was at the match -- which his team won 3-1 against Juventus -- to talk with UEFA chief Michel Platini about the Euro 2016 championships to be held in France.

But the trip has gone down badly in a country struggling through an economic crisis with more than 10 percent unemployment.

An opinion poll published on Wednesday showed that more than three out of four French people were "shocked" by the trip, which cost up to 15,000 euros ($16,900) according to government sources.

The prime minister said that taking his children on the flight "did not cost a single euro more", but has since pledged to repay 2,500 euros to offset the cost of his sons' travel.