PARIS—French police shut down on Saturday a huge party in northwestern France that had been under way since New Year’s Eve in defiance of a curfew and coronavirus restrictions on large gatherings. About 2,500 people had attended the rave party in an unused warehouse in Lieuron, near Rennes, and some clashed with police on Saturday, police said. Interior Minister Gerald Darmanin said on Twitter that party-goers were issued with fines as they left the site and organizers were being identified and would be prosecuted. The Ille-et-Vilaine prefecture said on Twitter 450 fines had been handed out for attending an illegal party, breaking curfew, and not wearing masks. Local health authorities urged party-goers to self-isolate for seven days. Prosecutors in Rennes have opened a probe into the illegal organization of a musical event and violence against persons of authority, the prefecture said on Saturday after the clashes. A police car caught …