French-Swiss director Jean-Luc Godard - a key figure in the Nouvelle Vague, the film-making movement that revolutionized cinema in the late 1950s and 60s - has died aged 91, French media is reporting.

French President Emmanuel Macron tweeted a tribute to the director, writing the country has lost a “national treasure.”

“It was like an apparition in French cinema,” Macron tweeted. “Then he became one of its masters. Jean-Luc Godard, the most iconoclastic of New Wave directors, had invented a resolutely modern, intensely free art. We lose a national treasure, a genius outlook.”

Godard’s first feature film, “À bout de souffle” (“Breathless”) in 1960, was a celebration of the nonchalant improvisational cinematography that became synonymous with his style.

In the years that followed, his films revolved around complex issues such as fickleness, indignity and caprice.

Among his notable later works were his “trilogy of the sublime,” which consisted of three films that explored femininity, nature and religion — 1982’s “Passion,” the following year’s “Prénom Carmen” (“First Name: Carmen”) and “Je vous salue, Marie” (“Hail Mary”) in 1985.

During his long career, Godard was awarded an honorary César in 1987 and 1998, and received an honorary Academy Award in 2010.

French newspaper Liberation was the first to report Godard’s death.