Feeling jilted after six months of negotiations, German officials reacted angrily Wednesday to General Motors’ decision to keep its European business, Opel, rather than sell a majority stake to a consortium backed by Berlin, The New York Times’s Nelson D. Schwartz, David Jolly and Bill Vlasic reported.

Expressing frustration with the U-turn, the new German economics minister, Rainer Brüderle, vowed to make the Detroit automaker repay the money that had already been lent. “We will get back taxpayers’ money,” he told reporters in Berlin, deeming G.M.’s move “totally unacceptable.”

Klaus Franz, the top labor leader at the company’s headquarters in Rüsselsheim, Germany, called it “a black day.”

“The path back to General Motors is something we won’t sign on to,” he added.

Opel workers, along with the German government, had strongly backed a sale to the Canadian-Austrian auto parts company Magna and Russia’s Sberbank, believing that would protect the most jobs. G.M.’s European operations include the Opel and Vauxhall brands.