A total of 4300 Swiss employees were hired by AXA, the French insurance company, for their usual salary in December. They had a happy surprise before Christmas, but they quickly lost their happiness when they knew they would not be allowed to keep the extra money.

AXA said the mistake, which was written by the daily newspaper Tagis-Ant Saiger and confirmed by the insurance company, occurred because of an error between the company and the bank that transfers the salaries, and employees have the choice between returning money or a salary in advance for the month of January.

AXA did not immediately disclose the amount it had mistakenly paid, but based on Switzerland's average annual wage of 85,000 Swiss francs, the excess may be over 30 million Swiss francs ($ 30 million).

"The worst thing could have happened ... The most important thing is that all the employees got a December salary before Christmas," an AXA spokesman told the paper.