Bayard Place has been sold for nearly £250,000 below its asking price by Peterborough City Council.
The council’s former city centre offices in Broadway were on the market for £6.2 million, but the authority accepted an offer for £5.95 million from Bayard Plaza Limited.
The council originally stated the sale was for £5.65 million but corrected that figure this morning.
It said it had accepted the highest bid it had received.
Negotiations to buy the offices have been ongoing for several months, with the building being put on the market by the council more than a year ago.
Investors were also being given the option to lease the entire building instead of buying it, or on a floor by floor basis.
Planning permission has already been granted to convert the offices into 115 flats with works expected to begin this spring.
The Peterborough Telegraph understands that Secret Millionaire Mike Greene, who featured on the Channel 4 show eight years ago, is involved in the project.
Boarding has already gone up around the premises.
The offices were until recently used for people to access housing advice, customer services, the police and free self-serve computer access.
Last month the council opened its new Customer Services in Bridge Street where those services are now being offered.
It is placed near the Town Hall, JobCentre Plus and Cross Keys Homes Customer Central building, meaning all drop-in services are on the same street.
Asked about the deal to sell Bayard Place, a council spokesperson said: “The offer was the highest we received following a number of bids on the open market for the property.”