The six men were arrested in a hotel room near Vienna airport as they tried to pass off five Picasso paintings for 50 million euros ($55 million), police said.
The buyer was in fact a police officer in disguise. Police commandos arrested the five Austrians and one Slovenian "in case they were armed," a statement said.
Subsequent raids in homes and cars found 14 fakes complete with forged artists' signatures and counterfeit certificates of authenticity signed by Picasso's son.
Counterfeit "El Greco". Photo: Austrian Police
Police also recovered 66 other works purported to be by 40 famous artists including Claude Monet and Gustav Klimt at the home of the Slovenian suspect.
The arrests took place earlier this year but were only announced on Monday.
The men, now on bail, said they believed the works were genuine, police said.