Tshisekedi landed at the Ndjili airport around midday after a trip to Europe, a member of his team said.
He was to travel on to his residence in Kinshasa’s Limete neighbourhood, where earlier Sunday four opposition activists were arrested by police using teargas to break up an unauthorised demonstration.
“We picked up three or four people who did not obey police orders. They will be set free,” national police spokesman Pierrot Mwanamputu told AFP.
Tshisekedi is the son — and successor in the opposition movement — of Etienne Tshisekedi, a longtime leading opponent of President Joseph Kabila. He died in February in Belgium, aged 84.
Kinshasa police had said Saturday that they were banning Sunday’s planned demonstration of the opposition coalition, saying they feared violent clashes.
The opposition parties have called for Kabila to step down. The president’s second term ended in December 2016 and the constitution bars him from standing for re-election.
The country’s authorities, which have yet to fix a date for the next election, promised on Thursday to quickly publish a “realistic” electoral timetable.
The political instability in the vast country of 70 million has raised international concerns.
One of the main obstacles to organising elections is the continuing violence in the central, diamond-rich Kasai region, where a rebellion has been going on for a year now, the electoral commission chief said last month.
Both the government and rebels are accused of atrocities in Kasai.