PARIS — It was supposed to be the site of the biggest airport in western France, a hub for cargo traffic and Concorde flights.

But instead, it became the center of a utopian experiment and an entrenched protest camp, one that challenged the government of President Emmanuel Macron.

In 1970, 3,700 acres of fields and woodland near the village of Notre-Dame-des-Landes were chosen for the new airport to satisfy a need first identified in 1965.

But in 2009, hundreds of protesters started squatting on the land, complaining of the project’s noise and the threat to wildlife. They set up shelters made of corrugated iron, wood and earthworks.