The comments from Interior Minister Bernard Cazeneuve came after the Stade de France in Paris, which will host the event's opening match and final, descended into chaos on Saturday before the national cup final after smoke bombs were set off inside the stadium, sparking panic among crowds that clustered at the stadium's exits.
Cazeneuve told the sports daily l'Equipe that the match between Paris Saint-Germain and Marseille "did not serve as a test" for Euro 2016.
"It was not the same public, not the same organiser, nor the same security deployment," he said. "However, what happened will be taken into account" ahead of the month-long football tournament, which kicks off on June 10.
"Our objective is that the Euro is a big festive gathering, but we owe the French the truth. Zero percent precaution means 100 percent risk, but 100 percent precaution does not mean a zero percent risk," he said.
"We are doing everything to avoid a terrorist attack, and we are preparing to respond. More than 60,000 police will be on the ground."
The Stade de France was targeted by suicide bombers during the attacks by the Islamic State group on the French capital in November. The assailants tried unsuccessfully to get inside the security perimeter.
Cazeneuve said security inside the stadium is the responsibility of Uefa, while safety at the "fan zones" -- which will accommodate seven million people in 10 host cities across the country -- is the mandate of private security agents.
"Fan zones are secure spaces, I took the decision to impose security pat-downs at entrances, to use metal detectors and to ban bags inside. If there were no fan zones, fans would regroup in an ad-hoc setting and the risk (of an attack) would be greater," he said.
Despite the beefed-up measures, he said there was no particular threat against the football tournament.
"At this time we do not have a specific threat to a specific team or a specific player, a specific match, or a specific fan zone," he said.
He added that protests would not be banned but did not rule out possible disorder as the country is gripped by a major labour strike.
"It remains an open possibility... that security cannot be guaranteed by law and order forces."
