Shares in state French power group EDF closed unchanged as they started trading in Paris in the world's biggest initial public offering so far in 2005.
EDF's part-privatisation was opposed by staff and unions
Its shares traded in a narrow range between 32 euros to 32.29 euros during the session.
The finance ministry said the 15% sale had raised 6bn euros ($7bn; £4bn).
Demand for the shares had been very high from private investors, but fund managers and analysts have complained that the price was too high.
The float values EDF at about 60bn euros, and it becomes Europe's largest listed utility company.
EDF's part-privatisation had been opposed by unions and staff, who staged a number of protests over the past year, ranging from organising general electricity blackouts to the targeted cutting of power to the homes of French government ministers.
To try and limit further demonstrations, the French government has pledged to maintain 85% ownership.
Private investors have bought 129,629,629 shares in EDF at a discount price of 32 euros each.
Another 58,239,339 shares were sold to institutional investors at 33 euros each.
"People are saying that the government priced it too high but on the other hand there are fund managers who need to buy because EDF will enter the CAC-40 index," said one Paris trader.
"The price will remain around 32 euros because the potential for a short term gain is limited."