We're told RiRi tattooed three of East Side Ink's artists with umbrellas and the letter R. None of her pet projects cared that she didn't have a license -- but the NYC Law Department does.
They say Rihanna could be slapped with three misdemeanors for the offense, each with its own hefty penalty -- as much as $300 for the first offense, $500 for the second and $1,000 for the third.
Sources say the tattoo shop could also face considerable fines of its own if the NYC Law Dept. decides to open an investigation.
UPDATE: The NYC Health Department just told TMZ: "Only licensed tattoo artists can administer tattoos in the city according to the City's Health Code. We are sending someone down to follow up on this."