The 21-year-old suspect was detained in Berlin on Monday evening over what local media have dubbed one of the biggest museum heists in modern history, a spokesman for the police in the eastern city of Dresden said.
The twins had eluded German authorities when they carried out raids last month and arrested three members of the Remmo clan, a family of Arab origin notorious for its ties to organised crime.
Police then named them as 21-year-old Abdul Majed Remmo and Mohammed Remmo.
All five suspects are accused of “serious gang robbery and two counts of arson,” Dresden prosecutors said.
Police did not immediately name the arrested twin. His brother remains on the run.
The robbers launched their brazen raid lasting eight minutes on the Green Vault museum in Dresden's Royal Palace on November 25th, 2019.
Having caused a partial power cut and broken in through a window, they snatched priceless 18th-century jewellery and other valuables from the collection of the Saxon ruler August the Strong.
Items stolen included a sword whose hilt is encrusted with nine large and 770 smaller diamonds, and a shoulderpiece which contains the famous 49-carat Dresden white diamond, Dresden's Royal Palace said.
The Remmos were previously implicated in another stunning museum robbery in the heart of Berlin in which a 100-kilogramme gold coin was stolen.
Investigators last year targeted the family with the seizure of 77 properties worth a total of €9.3 million, charging that they were purchased with the proceeds of various crimes, including a 2014 bank robbery.