Julian Assange, WikiLeaks founder, speaks in his first appearance ...

Julian Assange is back on European soil. When last here, he was behind bars.

On Tuesday, he gave evidence about his years of incarceration in a high-security UK prison, after the United States charged him under the Espionage Act.

It's his first public appearance since being released from prison and returning to Australia.

In an at times scathing address, he criticised the United States and its allies in their handling of his case.

A packed auditorium watched as Julian Assange spoke.  (ABC News: Mazoe Ford)

"I am not here today because the system worked, I am free today after years of incarceration because I pleaded guilty to journalism," Assange told Europe's leading human rights organisation, the Parliamentary Assembly of the Council of Europe (PACE) at Strasbourg, France, which is investigating his detention and conviction.

The appearance of the WikiLeaks founder at PACE was a tightly controlled affair, international media faced extensive restrictions, and Assange did not give interviews.

Assange told the ABC ahead of the hearing he was "pleased to be here."

'Isolation has taken its toll'

Flanked by his wife, Stella, and the WikiLeaks editor-in-chief Kristinn Hrafnsson, Mr Assange said legal protections "only existed on paper."

"I eventually chose freedom over unrealisable justice after being detained for years…. With no effective remedy," he said.

"Justice for me is now precluded because the US government insisted … that I cannot file in the European Court of Human Rights or a Freedom of Information request."

Speaking of his five years in a UK prison, Assange said it was a "relentless struggle to stay alive, physically and mentally."

"It strips away one's sense of self," he said. 

"Isolation has taken its toll.

"The transition from years of confinement in a max-security prison to being here before the reps of 46 nations is a profound and surreal shift."

The emotional address included some light moments too, with Assange thanking his wife for looking after his children while he was in prison.

The packed auditorium broke into laughter when he went on to describe how he is getting used to having a mother-in-law.

In his address, Assange focused heavily on the theme of freedom of speech.

"Freedom of expression and all that comes with it is at a dark crossroads," he said.

"The criminalisation of news gathering activities is a threat to investigative journalism everywhere.

"I was convicted, by a foreign power, for asking for, receiving and publishing truthful information, about that power while I was in Europe. 

"Journalists should not be prosecuted for doing their jobs. Journalism is not a crime, it is a pillar of a free and informed society."

Handling of Assange case blasted

Julian Assange focused heavily on the theme of freedom of speech. (ABC News: Mazoe Ford)

Assange is giving evidence after a PACE report into his case recently concluded he was a political prisoner.

That report called for Britain to hold an inquiry into whether he had been exposed to "inhumane treatment."

"While some of WikiLeaks' disclosures, especially those released in un-redacted form, could have posed a threat to the personal safety of informers, intelligence sources, and secret service personnel, despite the significant lapse of time, no evidence has emerged to suggest that anyone has been harmed as a result of them," PACE noted.

PACE said it considered the charges brought against Assange by the United States under the Espionage Act to be "disproportionate" and "severe."

"For their part, the UK authorities failed to effectively protect Assange's freedom of expression and right to liberty, exposing him to lengthy detention in a high-security prison despite the political nature of the most severe charges against him," PACE said.

"His detention far exceeded the reasonable length acceptable for extradition."  

After the hearing Assange told the ABC it was "good, but tiring." 

His wife said that although her husband was exhausted, it was "important" for him to address the council and she hoped it would "introduce safeguards so that what happened to Julian [could] never happen again to another journalist." 

Mrs Assange added that since her husband's release he had been enjoying family time.

"It's all we'd been wishing for for so many years, it’s wonderful," Mrs Assange told the ABC.

"We have been taking time for ourselves and time to figure things out."

Living as a free man after 14-year ordeal

In June this year, in the US Pacific territory courtroom in Saipan, District Judge Ramona Manglona sentenced Assange to five years and two months, the time he had already spent in prison in the United Kingdom fighting extradition to the United States, and said he was free to leave.

"With this pronouncement, it appears that you will be able to walk out of this courtroom a free man," Judge Manglona said.

Assange's guilty plea enabled him to come home to Australia in June this year, after spending 14 years away from his home country.

At the time, his wife Stella said he needed to adjust to normal life. 

"Julian needs time to recover, to get used to freedom," she said.

For seven of those years, he had been holed up in Ecuador's embassy in London, dodging a US extradition order. Ecuador does not have an extradition treaty with the US.

Assange's stay in the Ecuadorian embassy was dramatically cut short in 2019 when UK police entered the embassy and detained him, placing him in the country's high-security Belmarsh prison. He would be detained in Belmarsh for five years.

WikiLeaks and the wars in Afghanistan and Iraq

Julian Assange had been convicted under the US Espionage Act and faced extradition to the US. His plea of guilty to one count under the Espionage Act ensured his freedom.

Assange had been a fugitive since his organisation, WikiLeaks, published classified US military footage that showed the killing of Iraqi civilians and two Reuters journalists by US forces.

The April 2010 publication of the video, relating to an incident in 2007, sparked condemnation of the US military's handling of internal investigations, and led headlines across the world in publications like The New York Times and The Guardian.

Julian Assange pleaded guilty to one count under the US Espionage Act. (ABC News: Mazoe Ford)

A voice on the video transmission released by WikiLeaks urged the pilots to "light'em all up" before the group of individuals, which included two journalists, were fired at by a helicopter gunship.

The video showed a van arriving at the scene to pick up the wounded, before it too, was fired at by the US helicopter.

WikiLeaks went on to release a series of further explosive leaks which caused significant embarrassment to the US and its allies.

WikiLeaks published hundreds of thousands of documents leaked by former US Army intelligence analyst Chelsea Manning. That year, Chelsea Manning would be arrested by the US military over the leaks.

The documents related to the war in Afghanistan and revealed how the US military had killed hundreds of civilians in unreported incidents. Further documents from the Iraq war also revealed that as many as 66,000 civilians had been killed and that prisoners of war had been tortured by Iraqi forces.

Among that tranche of leaks were more than 250,000 messages sent by US diplomats which revealed that the US wanted to collect "biographic and biometric" information, which included things like DNA samples, iris scans and fingerprints, of key officials at the United Nations.

As global controversy grew of WikiLeaks' handling of leaking classified documents, major mastheads which had initially published WikiLeaks material began to distance themselves from the organisation, citing concern over checking source material and reducing harm to people potentially exposed in the massive tranches of documents.

The controversy spread further when, in 2010, Swedish prosecutors issued an arrest warrant for Assange on two separate sexual assault allegations, which Assange said were "without basis."

The charges would later be dropped in 2019, but the arrest warrant set off a series of events which would see Assange seek asylum in the Ecuadorian embassy in London, where he would live for seven years.

Impact on the 2016 US election

WikiLeaks' founder Julian Assange spoke before the Committee on Legal Affairs and Human Rights of the Parliamentary Assembly of the Council of Europe (PACE) in Strasbourg, France. (Reuters: Stephane Mahe)

The next significant release came in 2016, with the publication by WikiLeaks of thousands of hacked emails from the account of Hillary Clinton's campaign boss John Podesta, in the run-up to the US presidential election that year.

In the leaked emails, Mr Podesta called Mrs Clinton's election rival Bernie Sanders a "doofus", for criticising the Paris climate change agreement.

At the time, a furious Hillary Clinton campaign team blamed the leaked DNC emails on Russia, claiming election interference. Clinton went on to lose the election to Donald Trump.

On Wednesday, PACE will debate and vote on a draft resolution following on from Tuesday's evidence.