PARC Astérix has apologised after a photo was published appearing to show two performers dressed as Astérix and Obélix taking part in a Nazi-like salute.
The photo spread rapidly on Twitter, and shows three visitors to the park and two employees in costume doing the "quenelle", in which one places a palm across the opposite shoulder.
It is a gesture vaguely similar to the Nazi salute and is interpreted as having anti-Semitic overtones.
The "quenelle" was popularised by the French comedian Dieudonné, who stood as a candidate for an anti-Zionist party in the 2009 European elections.
Dieudonné was convicted last month for a seventh time of incitement against Jews and hit with a fine.
The gesture is being treated with increasing seriousness by French government officials. President Hollande has recently suggested legislating against it.
Parc Astérix said in a statement on Twitter: "Astérix and Obélix are - and will remain - apolitical. Our actors did not realise the significance of this gesture and we apologise for that."