Bemba's return to the DRC was announced by his party on Monday. Although expected, the relative ease of his homecoming has raised suspicion.
"How did [President Joseph] Kabila give without difficulty the diplomatic passport to Jean-Pierre Bemba?" Emery Kalwira, president of the opposition group, Congolese Coalition for Transition, told RFI.
Kabila’s government moved quickly to provide Bemba a passport after his release from prison last month, but has not granted the same privilege to other opposition leaders.
"I am a political leader, but I cannot put my feet in Kinshasa before Kabila goes out of power," continues Kalwira.
Neither can Moise Katumbi, the former governor of Katanga, who's still in forced exile in Europe.
"We don't have a passport. Last year, Kabila changed the passport to stop us from having the possibility to move around the world," said Kalwira.
The reason, according to him, is favouritism.
"That's why our coalition are supposing that there's a deal between Kabila and Bemba to share power and leave the Congolese population in a suffering situation."
Both men have shared power before, back in 2003 when Bemba was vice-president.
However, they're unlikely to do so again this time round, says government spokesman Lambert Mende: "You are resuming things that happened 10 years ago. The one who said it was telling you a lie! We have no problem with Mr Bemba," he told RFI.
For Mende, Bemba's return makes sense.
"He's a fellow Congolese. He had problems with the Central African Republic. He didn't have problems with us."
In June, the International Criminal Court (ICC) in The Hague overturned a 2016 conviction against Bemba on five counts of war crimes committed by fighters he sent to the Central African Republic in 2002-2003.
"He's a member of the senate," continues Mende, "he's a member of the parliament. He has never lost his quality of member of parliament, never," he said.
Under Congolese law, parliamentarians who've been out of the country for more than six months are barred from running in an election, as pointed out by Kalwira.
Suspicion was further fuelled earlier this month when Bemba's Movement for the Liberation of Congo party (MLC) held their annual congress and invited key members of government, including Emmanuel Ramazani Shadary, the permanent secretary of the People's Party for Reconstruction and Democracy (PPRD) of Kabila.
"We cannot understand how the opposition party can organize a congress and it invites the leaders of the majority in power," says Kalwira.
To which Mende replies: DRC is a democracy like any other, and that communication between the government and the opposition is normal.
Kabila status still unclear
There is however another problem: the status of Joseph Kabila, who still hasn't confirmed whether he will be running or not in the upcoming election, despite his second term having already expired in December 2016.
When Bemba last ran for office in 2006, he finished runner-up to Kabila. He still commands a large and loyal following in western Congo.
Analysts doubt that he would risk losing that support by teaming up with Kabila, and Bemba's deputy secretary general Fidel Babala dismisses the claims.
"He's coming here to submit his candidacy as candidate of the MLC opposition party, to bring about a transition," he told RFI, after the MLC confirmed Bemba as their candidate for the presidential polls.
The registration period opens this Wednesday 25 July.
"We've always made elections our key issue. It's not in making shady deals that we're going to bring about change in our country," he insists.
Bemba is free in Belgium pending a hearing on a separate conviction for attempting to influence witnesses, but is "happy to be returning home and seeing his supporters again," comments Babala.
"He's not coming here in a spirit of resentment. We can't build the future in focusing solely on the past, we must look ahead, and that's our programme in general."
3-way opposition split
The MLC will be vying for power along with two other opposition heavy weights: Moise Katumbi and Felix Tshisekedi, the son of historic opposition leader Etienne Tshisekedi, effectively splitting the opposition three ways.
Not forgetting the Union for the Congolese Nation party of Vital Kamerhe that's yet to confirm its intentions.
The more opponents there are, the more divided the opposition is, and the better the landscape appears for President Kabila.
Allies in his ruling coalition have in recent weeks advanced a legal argument they say would justify his candidacy.
The electoral commission for its part will publish the names of those who will run for election on 8 August. Government officials have so far declined to say whether Kabila's name will be among them.