German authorities are investigating whether three Syrians held on suspicion of working for so-called Islamic State had links to the Paris attackers, reports BBC News.
Interior minister Thomas de Maizière said the men, one of them 17, appeared to have been smuggled to Europe through some of the same channels.
They were detained after a series of pre-dawn raids in the states of Schleswig-Holstein and Lower Saxony.
They are said to have travelled through Turkey and Greece on false passports.
They have been named only as Mahir al-H, 17, Ibrahim M, 18, and Mohamed A, 26.
Investigations so far suggest the three came to Germany in November 2015 with the intention of "carrying out a previously determined order [from IS] or to await further instructions", prosecutors said in a statement.
The Federal Public Prosecutor's office has said no concrete missions or orders have so far been found, despite the seizure of "extensive material".
Mr de Maizière said those arrested could have constituted a "sleeper cell" - a unit of people who remain dormant and inconspicuous in a community until activated.
The suspects were arrested when 200 police and security officers raided six locations, including three refugee shelters.
The 17-year-old had been trained in handling weapons and explosives in Raqqa, IS's stronghold in Syria, prosecutors said.
They received fake passports, mobile phones loaded with a pre-installed communication programme and four-figure cash sums in US dollars.
At a news conference, Mr de Maizière said they were trafficked into Europe by the same organisation that supported the three men who blew themselves up outside the Stade de France national football stadium in Paris on November 13th last year.
A bystander also died - one of the total of 130 people killed in a series of co-ordinated attacks that night.
"Everything points to the fact that the same smuggler organisation behind the Paris attacks also brought the three men to Germany who were arrested," Mr de Maizière said. "Indications are that their travel documents all came from the same workshop in that region."
That showed that Western nations faced the same "shared threat" and thus "shared interests in the averting that threat" through security co-operation.