Italian police said in a written statement the audits of various businesses included ski resorts, hotels and bakeries, many of which had never bothered to pay their fair share.
"The biggest peaks in evasion were in the wholesale and retail sector, the construction business, the manufacturing business ... and housing and catering industries," the statement from the Guardia de Finanzia said.
About 2,100 individuals were caught up in the crackdown. Britain's The Telegraph said most had not filed tax returns for more than a year but still lived very comfortable lifestyles.
One hotel owner in Grado claimed he had simply forgotten to send in a return, the newspaper said.