The team president defended his club's ethical standards on Wednesday against the accusations, which led to questions in France over how betting is regulated and the influence of money on sports.
Montpellier, on track to win the national championship, lost its May 12 match against Cesson-Rennes 31-28. France-3 television reported late Tuesday that wives, girlfriends and other people close to the players bet against Montpellier at sites around France.
The TV report said eight Montpellier players were suspected of involvement, including members of France's gold medal-winning team from the London Olympics, and that the bets in question totalled €5,000 for an overall gain of more than €200,000.
Newspaper L'Equipe said team managers have been questioned.
An official with the French state-owned lottery and gaming agency, Francaise de jeux, told The Associated Press that it suspended betting on the match because of "unusual activity," including a sharp spike in the number of bets on the day of the game. It informed French authorities immediately.
The official spoke on condition of anonymity because the affair is in the hands of judicial authorities.
Montpellier president Remy Levy said in a statement that a preliminary investigation was under way but any information involving it was covered by French secrecy laws.
He appeared to be distancing club management from the players targeted, saying the team "vigorously protests" the implication that the club itself was involved.
"All the team's players are of course aware of the rules on sports betting and on the strict ban on participating in any way," he said. "Conclusions will be drawn by the club based on the result" of any investigation.
The French Handball Federation and the National Handball League stressed in a joint statement that the presumption of innocence must prevail but that any infractions "would be treated with the greatest firmness." They said their respective ethical guidelines forbid athletes or third parties to bet on competition or communicate any inside information.
Sports Minister Valerie Fourneyron saluted the "vigilance" of the gaming agency, but added in a statement that "no country or any sport is safe from risks of fraud linked to match-fixing." She assured France was "totally mobilized against this major threat."
The Montpellier prosecutor's office, reported to be leading the investigation, did not return calls seeking comment, nor did Cesson-Rennes.
Former Montpellier player Joel Abati expressed surprise at the TV report. But he added, in remarks shown on French television, "We are in a world of sport where anything can happen, you can be influenced."
The chief of France's online betting regulator, Jean-Francois Vilotte, said his agency Arjel was not involved in this investigation because the bets in question were made in person and not online.
He urged caution until the investigation was complete, saying alerts over irregular betting patterns were not unusual and most do not lead to criminal prosecution.
"It's perfectly normal that when there's a doubt, there's an investigation," he told The AP.
Still, he said the case highlights the need for better measures to regulate betting, especially betting across borders.