A combined TF1 and M6 would, however, hold sway over three-quarters of France's TV advertising market, a threshold likely to trigger alarm bells at the country's antitrust authority.
A source close to the matter said the companies had made informal approaches to the regulator ahead of the announcement.
The share of French TV in the overall ad in France, for example, has slumped 25% on average over the last two years, according to Kepler Cheuvreux, as viewers abandon traditional TV habits in favour of on-demand series, movies and shows.
"From a strategic perspective, the obvious aim is to create a French national champion with scale to compete with the global streaming giants," said Ian Whittaker, an independent analyst.
The idea that French antitrust regulations might be outdated when it comes to TV and advertising - and the sale of M6 in particular - has become a subject of debate within the watchdog.
Kepler, Ian Whittaker, Isabelle de Silva, De Silva
Monday, TF1, AT, Discovery, Netflix, Disney, Bertelsmann, Thomson
U.S, France, French