The French financial regulator AMF on Tuesday gave billionaire Francois Pinault three weeks time in order to present an offer for French utilities company Suez, Reuters reported.
According to the AMF, Pinault has time to launch the bid either alone or in partnership with others or to hold off for six months.
An offer by Pinault would further weaken a government-orchestrated plan for an 80-billion euro ($104.1 billion) merger between Suez and state-owned Gaz de France.
French President Jacques Chirac, a close friend of Pinault, later repeated his support for a tie-up between Suez and GDF, Reuters said.
Shares of Suez rose 0.1% to 38.87 euros, while GDF shares rose 1.52% to 35.60 euros.