The boards of directors of Suez (SZE.FR) and Gaz de France (1020848.FR) were meeting separately Wednesday, widely expected to approve the merger to create an energy giant despite vocal opposition of GdF unions.
The board votes in Paris would likely hand off the final approval to shareholders at each company, which executives have said they expected in a vote in July.
Any deal would also require the approval of market regulators.
Last month, GdF's works council rejected the planned merger, first announced in February, 2006, with the backing of the conservative French government. The French state holds a controlling stake in GdF.
The deal has been repeatedly delayed over legal efforts brought by GdF unions.
European Union regulators launched an in-depth antitrust probe last month into GdF, saying the bloc suspected the gas and electricity operator may have deliberately choked France's natural gas supply.
If the merger is completed, GdF Suez will be France's second-largest electricity producer and the largest gas importer and buyer in Europe.
The accord would give France a second global player in the politically sensitive energy market, along with Electricite de France, Europe's largest power generator, at a time when Europe is seeking to reduce its dependence on Russian gas and protect energy security.