French money manager Natixis is set to ink a deal today to move into 180,000 square feet in the base of 1251 Ave. of the Americas.

The company is leasing the third through fifth floors that were previously occupied by Avon.

Natixis’ move will consolidate offices currently spread between 9 W. 57th St. and 1345 Ave. of the Americas as well as employees already in 1251.

Back in May we told you that Natixis was focusing on this location.

John Cefaly and Rob Lowe of Cushman & Wakefield represented Natixis, while Peter Shimkin of Newmark Knight Frank repped the Mitsui Fudosan ownership. Both companies declined comment.

Asking rents in those Rockefeller Center west skyscrapers run in the $70s a square foot.

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The commercial office condo on top of Barneys at 660 Madison Ave. is being sold by its Italian owners. Risanamento SpA said it will be selling the building for a mere $10 million more than the debt of $275 million.

It bought the 254,000-square-foot boutique property from Broadway Partners for $375 million in 2007.

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The owner of the iconic Lipstick Building, Metropolitan Real Estate Investors, filed a bankruptcy petition for the building’s ownership entity as part of a plan to restructure its $210 million Royal Bank of Scotland loan.

The workout is being overseen by Eastdil Secured, which was initially hired to sell that loan along with another $60 million loan on 292 Madison Ave. that has already been sold to Morris Bailey.

The glamorous 602,000-square-foot building at 885 Third Ave. was once the site of Bernie Madoff‘s offices. Its nickname comes from its oval shape and mauve color.

Metropolitan bought it from Tishman Speyer for $648.5 million in another top-of-market 2007 deal.

To pay for the building, it sold about 79 percent of the land to SL Green Realty Corp. in a joint venture with Gramercy Capital.

The lease for the building has 70 years left and comes with an option to buy back the land. The building pays the landowners rent of $11 million a year and that amount bumps up in 2012.

The bankruptcy restructuring will entail a new ownership entity pledging all its assets to RBS.

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Sources say Eric Hadar is negotiating to hire starchitect Norman Foster‘s firm, Foster & Partners, to design a new contemporary tower that would overlook Bryant Park.

Foster is known here for the new Hearst Building’s jewel-like Crystal Cathedral and the four-story addition for Aby Rosen‘s 980 Madison Ave. project.

Complicating the construction on W. 40th St., sources say, Hadar has also signed CUNY to lease one of the buildings on the mid-block site between Fifth and Sixth avenues in order to provide income.

Hadar declined to discuss the project or lease. Nevertheless, sources say CUNY is expecting to take over the 91,000-square-foot 50 W. 40th St.

The 10-year lease, which sources say nets out to the mid-$30s a foot, still has to be approved by various city officials.

John Bonamusa of JJ Bonamusa & Associates approached Hadar and suggested the CUNY deal.

He could not be reached for comment. Howard Kesseler of Newmark Knight Frank is representing CUNY and declined comment.

Other sources say CUNY would create a new community college to act as a “feeder” to its larger four-year programs.

The small building is perfect for a school, as it is currently being used by the Katherine Gibbs School, which spent some $20 million on creating classrooms and upgrades.

Career Education Corp., its Chicago parent company, wants to gets out of its lease, which goes to December 2015, and has been unsuccessfully trying to sublease.

Hadar also owns the adjacent 43 W. 39th St. along with the 51,000-square- foot Daytop Village Building at 54 W. 40th St.

With 130 feet along Bryant Park and a slew of air rights, Foster’s options in clude designing a building of up to 300,000 square feet that would canti lever over 50 W. 40th St.

The seven-story black-and-gold 50 W. 40th is an annex building to its taller neighbor, the Raymond Hood-designed, landmarked American Radiator Building, which houses the Bryant Park Hotel.

Hadar’s smaller annex has 30-foot-high ceilings on the ground floor with a group of large windows overlooking the park and a number of setback terraces flocked with gold.

While not landmarked, sources say any future development would likely maintain the façade and simply build up and over the annex.

Development plans for the ultra-modern tower, which could include office, hotel and residential spaces, were first revealed by Post colleague Jennifer Gould Keil last month.

A year ago, Hadar bought out his father, Richard Hadar, from the buildings. His parents are divorced and his mom, Margery Hadar, is the Brown Harris Stevens agent marketing his breathtaking $26.25 million city apartment on E. 65th St. with 360-degree views.

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Nasdaq-listed SS & C Technologies is more than doubling in size at 675 Third Ave. on the northeast corner of E. 42nd St.

SS&C develops financial-investment management software that includes the popular Skyline Property Management Software for real estate.

The firm currently occupies 20,000 square feet on the 14th and 15th floors. When completely moved in, they will occupy the 12th and 14th through 17th floors, totaling 50,000 square feet.

As with many superstition-influenced office buildings, there is no 13th floor. According to CoStar, the asking rent was $52 a foot.

The tenant was repped by Michael T. Cohen, president of the Colliers International tri-state region, along with its Vice Chairman Leon Manoff.

The Durst Building was represented by its in-house leasing team of Tom Bow and John Grotto.

While the building’s floor sizes average 12,700 square feet and some are multi-tenanted, Grotto said it worked to the tenant’s advantage, as they’ve already expanded six times.

Rather than, say, moving to two, 25,000-square-foot floors in another building that would limit its future expansion option to 25,000 feet at a time, the Durst leasing team provided future growth possibilities in roughly 5,000-foot mouthfuls, Bow said. [email protected]