Dozens of energy sector unionists burned tires and hung banners outside the Cordemais coal plant in western France to insist that energy is a public good.
"Today, we are mobilized for our wages of course, because EDF has had record-breaking results, and we would like to reap the fruits of our work," CGT union representative Mathieu Pineau said.
The CGT called for the strike after it deemed the results of negotiations on wages in the energy sector unsatisfactory at the end of last year.
Various sites such as the Cordemais coal plant operated by French utility EDF were blocked by striking workers on Tuesday.
French power group EDF's workers are also set to go on strike on Wednesday (January 26), following the main trade unions' call to protest against a government plan to increase the amount of cheap energy EDF must sell to rivals at under-market prices, which would hit EDF's results.