Total's chief executive Patrick Pouyanne said on Friday he had not given up on the idea of keeping Britain in the European Union.
The French oil major, Europe's second-largest, is a major oil producer in the British North Sea.
"I still hope that Britain remains in the European Union," Pouyanne said on the sidelines of a business conference in the southern French city of Aix-en-Provence.
"Maybe what will happen under the initiative of Emmanuel Macron and (Angela) Merkel will pave the way for a new future for Britain," Pouyanne said, referring to the new French president and the German chancellor, without elaborating.
The current period of economic uncertainty triggered a year ago by the British vote to leave the EU needs to end as soon as possible, Pouyanne addded.
"What's not good for Britain is that we're in a period of uncertainty," Total's boss said. "Investors don't like uncertainty."
"Britain's interest is to clarify things quickly. It's also in the interest of Europe," he added.
(Reporting by Michel Rose, Mathieu Rosemain and Gwenaelle Barzic)