A hustler who claimed he was the nephew of real-estate mogul Leonard Stern was arrested in an investment scam that bilked $100,000 from a victim he met at a swank Midtown cigar shop, authorities said yesterday.

Gary Stern, 46, who’s not related to the mega-rich developer, was charged with grand larceny for allegedly persuading the man to invest in what Stern said was a 600-unit apartment complex in Brooklyn.