PARIS (Reuters) - The European Commission was right to order Apple to pay 13 billion euros ($14.48 billion) in back tax, French Finance Minister Michel Sapin said on Thursday, backing Brussels as tensions flare with Washington over the ruling.

"The European Commission treated it as abnormal state aid... the European Commission is doing its job," Sapin told a news conference. "It's normal to make Apple pay normal taxes."

The United States has accused the European Union of grabbing revenue intended for U.S. coffers with the decision, comments that could cause friction at an international summit in China next week.

(Reporting by Leigh Thomas and Yann Le Guernigou; Editing by Andrew Callus)