Michel Barnier, the new French prime minister, did not thank President Emmanuel Macron for appointing him in his first remarks upon taking office last week. This was a declaration of independence.

The remarks were pointed in other ways. “We will certainly act more than we talk,” Mr. Barnier, 73, a pragmatist of the center-right, said, with a verbose president clearly in mind. He added that wisdom often comes from the poorest and humblest members of society “if one takes the time to listen.”

Again, the little barb was clearly pointed at a remote Mr. Macron, often impervious to counsel and dismissive of the needy.

This was a moment of “rupture,” in Mr. Barnier’s words. It was the end of an era, the return of the French old guard summarily evicted from the political arena when the upstart Mr. Macron triumphed in 2017; and it came at a moment when not even the lingering glory of the Paris Olympics can obscure the economic, social and political crisis faced by France.

During his seven years in office, Mr. Macron, 46, never before encountered, nor would he have tolerated, such conduct from prime ministers, who sometimes seemed little more than his pliant playthings. But, with almost three years left of his presidency, he is weakened. His party is no longer the largest in a fractured Parliament, his popularity is low, and his judgment is questioned.