One of the most unusual office floors in Midtown has been rented to the real estate investment firm GTIS Partners.

Now at nearby 45 Rockefeller Plaza, the company will move to the 28,677-square-foot 50th floor at the Axa Equitable Building at 787 Seventh Ave.

The dramatic space has huge arched windows on each end of the floor, providing superb views. Portions have soaring ceilings — up to 40 foot high — and there are overlooking mezzanines on the 51st floor accessed by private interior elevators.

Rocco Laginestra, Michael Laginestra and Scott Gottlieb of CBRE represented the tenant, which is moving and expanding from its current locale.

Howard Fiddle and Keith Caggiano of CBRE represented the building owner, CalPERS and its advisers, CommonWealth Partners, which sources said had a “triple digit” asking rent with “strong” concessions.

The California-based owners made a splash in early 2016 when the deal closed for $1.9 million.

For GTIS President Tom Shapiro, having the former Equitable and later Citibank space for his global real estate investment firm’s office is like a homecoming.

“When I joined Tishman Speyer in 1988, they were the developers [of the building],” he recalled. “Part of it was the white tablecloth cafeteria where I used to have lobster for $4, and the rest was a boardroom. I heard it was available but it had been vacant for 10 years because no one could figure out what to do with it. We are really excited to repurpose and redesign it to make it special.”

Building amenities include an auditorium, an Athletic & Swim Club with an Olympic-size swimming pool, plus upscale restaurants Le Bernardin and Bobby Flay’s Bar Americain.

The lobster, however, is much more than $4 a pop.