The buyer is Engie Deutschland GmbH, a technical building services, facilities management, industrial refrigeration technology and energy services company in Germany.
Financial terms were not disclosed. Deal completion is still subject to the approval of the relevant competition authorities.
Otto, purchased by Equistone in May 2014, offers ventilation and air-conditioning solutions, cooling technology and building automation services.
DC Advisory provided M&A advice to the firm, while P+P Pöllath + Partners served as legal adviser, Deloitte as financial adviser, KPMG as tax adviser and PwC as commercial adviser. Baker Tilly and Göhmann advised Otto's management team.