Berlin police say that Luka Rocco Magnotta is being questioned and will be brought behind closed doors before a judge, who will read out the international arrest warrant later.
Officers arrested him on the site, he did not put up any resistance. He says he is the wanted person.
Interpol has placed Magnotta, who was last believed to be in Paris, on the equivalent of its most-wanted list.
More top news
The chief executive of one of the 'big six' energy companies tells ITV News a report customers are paying too much is a concern.
10 years on, George Psaradakis has given his first interview, recalling the events of July 7 2005.
A spat between the supporters of Yvette Cooper and Liz has seen a debate rage over whether a woman needs to be a mother to be a good leader.