Minister Laurent Nuñez said on Sunday that the government wants to stop illegal rave parties.
"To ensure this, the punishment will be harsher," Nuñez said. He traveled by helicopter to his hometown of Bourges near the party site.
Organizers of this weekend's party, at a military training area, said the location was chosen in part to challenge the minister's demands for tougher penalties.
Ahead of the party, authorities warned that unexploded ammunition from World War II could pose a life-threatening danger.
On Sunday evening, no explosions had been reported, but bomb experts defused a grenade in the area.
