It was in August that Alexei Navalny flew to Berlin after being poisoned with novitiate, a neurotoxin that developed in the then Soviet Union.
He, and several countries with him, have accused Russian President Vladimir Putin of being behind the poisoning - something the Kremlin denies.
Now, on Sunday afternoon, critics of the regime are returning to Moscow.
At 13.50, the plane that will fly home Alexei Navalny landed at Brandenburg International in Berlin, where the media presence is large.
Even at Vnukovo Airport in Moscow, the uproar is great with a large police force and a prisoner transport waiting for Alexei Navalny.
Thousands want to meet Navalny
At the same time, at least 2,000 people have stated on Facebook that they plan to meet Alexei Navalny at the airport.
Another 6,000 people have expressed interest in the event, despite the capital reporting thousands of new corona falls daily.
The collection is seen by the authorities as illegal as it has not received permission.
Alexei Navalny, who is accused, among other things, of violating the terms of a suspended prison sentence for embezzlement in a case from 2014, is a major concern for the Kremlin.
An arrest can lead to international criticism, in addition he may be seen as a political martyr.
Not arresting him, on the other hand, could portray the Kremlin as a weight.
Has revealed elite corruption
Alexei Navalny may pose a threat ahead of the parliamentary elections to be held in Russia this autumn as he has managed to reach young voters through viral videos in which he revealed corruption among the elite, and he has more than two million followers on Twitter.
According to him, all criminal charges are fabricated and politically motivated.