The move will raise up to 7 billion euros ($8.4 billion) from the public in the world's largest flotation in four years and is designed to bolster the world's largest nuclear power producer as it faces market liberalisation in Europe.
As French unions repeated their opposition to what one described as an "ideological and dogmatic" move, Prime Minister Dominique de Villepin wrung concessions out of EDF on tariff increases and investments before finally giving the green light.
"The opening of EDF's capital will be a fine example of popular share ownership in France," Villepin said. He told a news conference the French state would keep at least 85 percent of what has until now been a jealously guarded state utility, after opening up its capital to the public.
With all the money going to the company itself, the government will not be using the sale to raise cash to reduce its huge public debt.
It will sell around 1 billion euros worth of existing shares to EDF staff and has also drawn up plans to sell French motorways in a less controversial bid to cut debt by some 11 billion euros.
Fund managers said the success of the initial public offering looked fairly certain.
"I should think there is appetite for the stock. All of this of course will depend on its price, but there has been a lot of pent-up (demand) around the stock; the IPO has been well flagged so the market has been waiting for it," said Nishit Shaah, investment manager at Sarasin Chiswell in London.
The pricing range will be announced on Friday morning.
With 296 million new shares being offered to the public and taking in the 7 billion euro ceiling, the average price for the shares would theoretically be 23.6 euros apiece, around the same level sister firm Gaz de France went for in a July flotation.
At 7 billion euros the deal would be the world's largest IPO in dollar terms since Kraft Foods of the United States in 2001, according to financial data provider Dealogic.
A strong turnout in an October 4 general strike against government reforms and a separate dispute over the privatisation of a Corsican ferry firm had raised doubts over the timing of the sale of 15 percent of EDF's capital.
Villepin pushed ahead with the sale after EDF promised to link tariff increases to inflation for five years and to raise the amount it planned to invest, boosting the scope for jobs.
The issue of tariffs was clouded, however, by a simultaneous and potentially embarrassing row between the government and Gaz de France over a 12 percent hike in gas bills planned from November. Finance Minister Thierry Breton said he opposed it.
Raising its target, EDF said it would invest 40 billion euros over five years including 30 billion euros over three years from 2006.
Initially, EDF set out plans to invest 26 billion euros over three years, but Villepin intervened at the last minute for the figure to be raised.
Villepin and Gadonneix have also signed a deal guaranteeing the provision of public services to meet government conditions over the social impact of the selloff.
Despite these pledges, Communist Party leader Marie-Georges Buffet called on Monday for a united front among France's bitterly divided Left to fight the partial privatisation.
The larger Socialist party, which leads the opposition, has already promised to denationalise EDF if re-elected in 2007.