Auschwitz-Birkenau State Museum has banned people from playing Pokémon Go on their smartphones during visits to the former death camp.
Authorities at the museum said they introduced the ban because playing the game on the premises was "disrespectful on many levels".
The ban comes after reports of people playing the game at Auschwitz and other memorial sites around the world.
A spokesman for the Auschwitz memorial in Poland wrote on Twitter: "Do not allow playing #PokemonGO on the site of our Memorial and similar places. It's disrespectful on many levels."
Pokémon Go is a new hugely popular reality game that uses GPS, and allows players to search locations in the real world to find virtual little creatures.