It’s the best lease in the city.

In 2009, Jud Parker got a West Village landlord to give him a ­duplex apartment on tony Minetta Street for $10 a month — for 50 years!

Now new landlord Pari Dulac is challenging the sweetheart deal and claiming the old owner, who died in 2010, had dementia when it was allegedly signed.

“When I saw the lease, I couldn’t believe it,” said Dulac, a longtime Village resident. “I thought it was a joke.”

Wilfred Schuman, a German-born ballet dancer, had owned a pair of three-story town houses at 12 and 14 Minetta St. since 1993. He lived in the basement of

12 Minetta St.

According to the August 2009 lease, Parker and gal pal Stefanie Tyler pay just $10 a month for the 1,400-square-foot duplex at 14 Minetta St., which has two bedrooms and a back yard. The 50-year lease has a 10-year renewal option.

In a lawsuit filed in Manhattan Supreme Court Friday, Dulac claims Parker bamboozled Schuman, who was in his 70s — then subletted the apartment for $2,500 a month after his death.

The suit claims Parker manipulated Schuman into signing the lease or forged his signature.

Dulac bought the buildings from Schuman’s estate last week for $2.75 million. She believes she could rent Parker’s pad for $6,000 a month — which, ironically, is equal to what Parker would pay over the course of his entire half-century lease.

But Parker, 47, who was making repairs to the apartment Friday, said the lease was a “gift.”

“I was a surrogate son. I took care of him my whole life,” Parker said. “[Dulac] wants me out because she’s greedy.”

Parker, who declined to comment further, grew up across the street from Schuman. He bought a condo in Davie, Fla., in 2006, rec­ords show. His lease also lists the Florida address.

Schuman was admitted to hospitals from 2007 to 2009 for alcoholism, dementia and bleeding of the brain after a fall, the lawsuit alleges. Dulac also has an affidavit from Schuman’s brother, Volkmar, who lives in Berlin and corroborates his brother’s dementia.

In affidavits, residents described Schuman as paranoid, reclusive and “often drunk by late afternoon.” He ate little, “besides cans of tuna fish, which he shared with his cats,” one tenant said.

David Burnett, who lived above Schuman, opened a bank account in the ailing landlord’s name so tenants could deposit monthly rent checks that Schuman was ­incapable of accepting.

Schuman refused to offer tenants formal leases beginning in 2007, and residents lived month to month.

In an affidavit, Burnett said he encountered Parker in his building in 2009, but had seen him only twice before over a period of

20 years. Burnett grew suspicious after Parker and Tyler started hanging around Schuman’s pad for three weeks in 2009. He didn’t see Parker again until June 2010 — when he asked where the rent should be paid.

Laurie Dowdeswell, who lived at 14 Minetta St., said Parker asked for Schuman in August 2010, unaware that he had died, according to the lawsuit. A day later, Parker presented her with the lease and claimed it was his apartment, according to the suit.

Parker allegedly demanded she sublet for $1,500 a month or vacate the apartment. Her rent increased to $2,500 two years later — which was $350 cheaper than what she paid Schuman.

Parker didn’t have keys to the apartment until October 2014 ­after Dowdeswell and her husband left, the lawsuit alleges.

“This lease is outrageous and unconscionable,” said Dulac’s ­attorney Steven Sladkus.