"We're using it now for the first time re: a group deemed illegal in Germany."
In a separate tweet, Macgillivray posted a link to a message from the police in the northern German state of Lower Saxony asking Twitter to block the account of Besseres Hannover, a far-right outfit which was outlawed last month.
The account is still visible on Twitter with the handle @hannoverticker and calling itself "the national information portal from Hanover".
But no message since the date of the ban, September 25, is visible in Germany, and the group's website has also been blocked or deleted.
Prosecutors in Lower Saxony have launched a probe against around 20 members of Besseres Hannover on charges of inciting racial hatred and creating a criminal organisation.
The group is in particular suspected of sending a threatening video to the state's social affairs minister, Aygul Ozkan, who is of Turkish origin.