As the wan winter sun sets over France’s Champagne region, the countdown clock kicks in. Laborers stop pruning the vines as the light fades at about 4:30 p.m., leaving them 90 minutes to come in from the cold, change out of their work clothes, hop in their cars and zoom home before a 6 p.m. coronavirus curfew.

A French prosecutor said police detained seven people Saturday, including two alleged organizers, after a New Year’s Eve rave party drew at least 2,500 people in western France despite a coronavirus curfew and other restrictions.