EDF chairman and chief executive Jean-Bernard Levy did not know that the UK government would review the Hinkley Point project and is planning to sue a union for stating otherwise.
The company said Levy had no prior knowledge of the new government's decision to review the nuclear power project.
In a statement, EDF said Levy would take legal action against French union Sud Energie for claiming he lied to the media by stating he had not known before the board meeting that Britain would conduct any review.
"Reading the entire internal email sent on 2 August by the chairman and chief executive of EDF to members of the executive committee confirms unambiguously that when the company's board of directors was held, EDF and its chairman had no knowledge of the intention of the British government to conduct a further review of the Hinkley Point project," the company said.
"All that was known before the press statement issued by the British government on 28 July was that the signing ceremony originally proposed for Friday, 29 July, would be postponed.
"This potential date of signature had not been confirmed, and therefore had not been communicated either to the board nor the market. There was therefore no requirement to communicate its postponement."
However, Sud Energie has stood by its comments. The unions have warned that the project is too big and puts the company at risk.
Last week a French count upheld EDF's investment decision, rejecting a challenge by the company's work council.
Prime Minister Theresa May said the government wanted more time to assess the plan, aiming to make a decision later this year.