Luxembourg's Griffin Real Estate and U.S. investment fund Pimco have agreed to buy Polish billionaire Michal Solowow's 41.55-percent stake in business space developer Echo Investment, the Polish company said late on Friday.

The deal, in which an entity belonging to Griffin and to a Pimco-managed fund will purchase the stake, was signed on Feb. 28 and needs to be approved by the antimonopoly watchdog, Echo Investment said in a statement, without giving any further details.

The Polish developer, which is listed on the Warsaw bourse, has a total market value of $720 million. Solowow's plans to sell his stake were first reported in July 2014.