The restaurant in Venice which hit the headlines after charging four diners around €1100 (NZ$1800) for four steaks, fried seafood, a bottle of wine and water, is making the news again.
It also faces other infringements including issues over the accurate description of goods.
The La Nuova Venezia newspaper said the investigation could “produce total fines running into tens of thousands of euros”.
The Mayor of Venice Luigi Brugnaro hit out at the eaterie after the €1100 bill was doled out to the Japanese tourists.
“If this shameful event is confirmed, we’ll do everything we can to punish those responsible,” he said on Twitter.
The restaurant has a rating of 1.5 stars on Tripadvisor.
Venice, one of the world’s most popular tourist cities, has a reputation for brazenly overcharging its visitors.