PARIS (Reuters) - French energy group Engie expects to have a shortlist of would-be buyers for its Equans services unit by the end of September, according to two sources familiar with the discussions. U.S. investment firm Apollo Global Management Inc is among the seven firms that have submitted non-binding offers for the unit, according to the sources. Equans provides energy and facilities management services to client companies and employs around 40% of Engie’s total workforce worldwide. The value of the deal is estimated at around 5 billion-6 billion euros ($5.94 billion-$7.12 billion), according to sources close to the deal. The sources said the company is expecting to shortlist potential buyers by the third week in September, who will then be given access to company data. It expects binding offers around the end of November, and to select a buyer by year-end, they added. Engie’s press service declined to comment. A representative of Apollo could not be reached for comment. French firms Bouygues, Eiffage and Spie have each already said they have submitted offers. Several sources close to the deal have previously told Reuters that offers were also submitted by Bain Capital, Carlyle Group Inc, and CVC Capital Partners acting in conjunction with France’s PAI Partners. Bain Capital, CVC-Pai Partners and Carlyle declined to comment. Additional reporting by Benjamin Mallet; Writing by Christian Lowe and Gwenaelle Barzic; Editing by Jan Harvey Our Standards: The Thomson Reuters Trust Principles.