After 10 years in a Russian gulag, Mikhail Khodorkovsky tells of the 'unbelievable feeling of freedom' as he is reunited with his family in a Berlin hotel

Berlin's Hotel Adlon, which overlooks the Brandenburg Gate and is sandwiched protectively between the US and British embassies, knows how to welcome its guests the traditional German Christmas way – with huge amounts of luxury gingerbread.

The first thing that Mikhail Khodorkovsky would have seen when he entered the most historic of all five-star establishments in Berlin would have been a large, illuminated model of the hotel itself, made of cinnamon-flavoured sweetmeat. That's if he came in the front way – none of the reporters who had been waiting freezing outside since 6am had seen the Russian oligarch or any of his family coming in or out all day.

Khodorkovsky's son Pavel, who arrived from the United States early yesterday morning, was the first family member to greet the Russian oil tycoon, released from a prison in Segezha, northern Russia, on Friday. Somewhere inside the hotel, the ex-richest man in Russia was also enjoying a reunion with his parents Marina and Boris, who had flown in from Moscow in the early afternoon. "After 10 years, it's an unbelievable feeling of freedom," Khodorkovsky wrote in the Russian New Times early in the morning. "The most important thing is: freedom, freedom, freedom."

"I just want to hold him in my arms," his mother had told the news agency Reuters on Friday, as she prepared to come to Berlin. "I don't know what I will tell him yet."

Then, shortly after 3pm, Pavel appeared briefly on the Adlon's steps to say in English: "I'm thrilled to be in Berlin today because my father is free. As you can imagine, my father is going through a lot right now."

"It's good that he's free," said one Russian tourist, hopping in the cold and waiting for a guided tour outside. "He's a symbol of the opposition for us, but I don't know if I'm happy. He didn't ask for this pardon for so long, and now he asked for it, and I don't know what lies behind this. I hope it's not because he was broken."

Ewald Böhlke, head of the Russian section of the German Council on Foreign Relations (DGAP), knew Khodorkovsky before his arrest in 2003. Böhlke, a businessman at the time, worked with the Russian a decade ago to develop "mobility concepts" for Yukos, the petroleum company that Khodorkovsky built up in the 1990s.

"I was on a panel trying to help optimise his company," he told the Observer. "I only knew him professionally, but I remember it was a lot of fun. I hope the first thing he does is find a psychologist. I don't know if you can imagine what that's like – 10 years in a gulag.

"After that, I think his priority will be helping Platon Lebedev, his business partner," said Böhlke. Lebedev, who was convicted of tax fraud alongside Khodorkovsky in 2003, is still behind bars, and the Voice of Russia reported that Lebedev had said that he has "no intention" of appealing for a pardon.

According to Böhlke, pressure from the Russian business community was more instrumental in securing Khodorkovsky's pardon than any higher-profile foreign policy initiatives or the reaction to human rights abuses in Russia. "It had nothing to do with Sochi [2014 Winter Olympics]," said Böhlke. "Of course, it was an ingenious trick by Putin to announce it now."

The importance of economic factors could be gleaned from a comment by Eckhard Cordes, the chairman of Germany's Committee on Eastern European Economic Relations, who told the financial daily, Handelsblatt: "The Khodorkovsky case has without doubt burdened the business climate in Russia. His release is an important step towards improving international trust in Russia as a location."

Former German foreign minister Hans-Dietrich Genscher, who met Russian President Vladimir Putin twice to negotiate his release, was also vital. It was during his tenure as president of the DGAP from 2001 to 2003 that Genscher met Khodorkovsky, then at the height of his power as head of Yukos. And it was at a DGAP event in September 2003 – in the Hotel Adlon – that Khodorkovsky gave a lecture that Böhlke, who was also present, said became a "key moment" in the cementing of ties.

German news agency DPA reported that Khodorkovsky had received a visa allowing him to stay in Germany for a year, but all speculation on his plans – there were rumours that he would travel to the UK or Switzerland or return to Russia – was put off until Sunday afternoon, when Khodorkovsky has called a press conference – at another must-see sight for Berlin tourists: the Berlin Wall museum at Checkpoint Charlie.

• This article was amended on 22 December 2013. Hans-Dietrich Genscher was referred to as the current German foreign minister. This has now been corrected.