PARIS — Blaise Gauquelin, the Central Europe correspondent for Le Monde, called his editor at the paper’s Paris headquarters one day last fall to pass along something of interest: One of the two French businessmen who controlled the 75-year-old daily was selling part of his stake to a Czech billionaire named Daniel Kretinsky.

The news sent a tremor through the newsroom of the august national publication.

Le Monde’s journalists looked into Mr. Kretinsky and noted that he had built his fortune largely on power plants and coal mines across Europe. He also owns part of a pipeline that brings Russian gas through Slovakia to the West. Why would an international energy magnate be interested in an anti-Kremlin newspaper that had invested heavily in covering climate change?

Mr. Kretinsky’s earlier foray into French media, the purchase of the center-left newsweekly Marianne for 5 million euros last year, contributed to the staff’s wariness, given that his first big move was to install the conservative commentator Natacha Polony as editor.

Mr. Kretinsky, 43, has had a rapid rise under the tutelage of two of the most successful privatization barons in the post-communist Czech Republic and Slovakia, Patrik Tkac and Petr Kellner. His main business, EPH, comprises more than 50 companies and has annual revenue of 6 billion euros.