The majority want him to leave when his term ends in December, but he says elections will be delayed until 2018.
Joseph Kabila said he hopes 10 million more voters will now register for the 2018 election.
Kabila has been accused of trying to stay in power by delaying elections in Congo.
Elections scheduled for November look likely to be delayed until at least July 2017.
The Congolese government has expelled several foreign researchers already in 2016.
The judge claims the government wants to cripple Katumbi's political ambitions.
Darryl Lewis worked for opposition presidential candidate Moise Katumbi, a challenger to President Joseph Kabila.
The football club owner and presidential candidate has been accused of recruiting mercenaries.
Katumbi, the owner of a football club, announced he would run for the Congolese presidency last week.