Weiwei claimed that the treatment of Assange bore similarities to the way Chinese authorities suppress dissidents.
The Wikileaks founder is fighting against being extradited to the United States where he faces espionage charges.
Julian Assange allegedly had two children by his lawyer while he was staying in Ecuador's embassy in London.
One of the lawyers for Assange, who is in a UK jail, told Euronews his client had been "weakened by detention conditions which are absolutely extraordinary".
WikiLeaks founder Julian Assange appeared in a London court on Monday for a hearing on whether he should be extradited to the United States to face spying charges.
Swedish prosecutors filed a request for Julian Assange's arrest over rape allegations they are investigating.
MEPs have backed new EU laws to protect employees who go public with reports of wrongdoing. The new rules protect whistleblowers from dismissal and offer safe channels for reporting abuses. The reforms come amid debate over the fate over Wikileaks co-founder Julian Assange.