EDF said it appointed its finance head for France, Xavier Girre, 47, as group chief financial officer after former CFO Thomas Piquemal quit the French utility.
EDF said the appointment was provisional and with immediate effect. The company did not say why Piquemal resigned.
A source familiar with the situation said on Sunday that the CFO had concluded EDF's 18 billion pound ($25.5 billion) Hinkley Point project to build two Areva-designed European Pressurized Reactors (EPRs) would put too much stress on EDF's already stretched balance sheet.
EDF shares were down 7.8 percent at 0849 GMT, the top losers on the French blue-chip CAC 40 index.