The masked gang burst into the Grand Hyatt hotel in central Berlin, where the tournament was taking place, threatening security staff and prompting a brief panic, police spokeswoman Heidi Vogt told AFP.
Berlin’s Tageszeitung newspaper reported on its website that six raiders armed with Kalashnikov assault rifles and grenades made off with 800,000 euros ($1,200,000).
Gawker has video of the harrowing scene, as it was broadcast on television.
“Several masked, armed individuals entered the Grand Hyatt and fled with a haul of money,” the police said.
A number of the tournament’s players were injured in the incident, though none were seriously hurt.
Four of the attackers entered the hotel from Potsdamer Platz, one of the German capital’s most important and popular squares, while two others kept watch, the Tageszeitung reported.
A security guard briefly stopped one of the robbers, who hit him over the head with a weapon and fled, the newspaper said.
Nearly 1,000 players are to take part in the five-day poker tournament.