More than 200 Hitler-lovers from France, Germany and Italy descended on the Alsace village of Oltingue on Easter weekend to mark the Nazi leader’s 125th birthday on 20 April.
Police said that they heard about the event on Saturday evening when it was already under way and that it would have been “legally complicated” to force it to be called off.
A number of gendarmes were sent to the scene to “ensure calm and tranquillity”.
Oltingue mayor André Scherrer says that he had no idea that the “private party” was in fact a fascist get-together.
“We were tricked and I regret it,” he told local media.
A concert with several rock groups playing had been advertised on the internet several months ahead without giving details of the venue until the last minute.