Becker, 50, was declared bankrupt by a British court in 2017 in connection to a debt to private bankers Arbuthnot Latham & Co. He has recently been pursued for "further assets", according to a statement by his lawyers.
The German former world number 1 lodged a claim at the High Court in London to halt the case because his appointment as Attache to the European Union on sporting, cultural and humanitarian affairs entitled him to immunity under the 1961 Vienna Convention on Diplomatic relations, the statement said.
Becker said the proceedings against him were "unjustified and unjust".
"I have now asserted diplomatic immunity ... in order to bring this farce to an end, so that I can start to rebuild my life," he said in a statement.
"I am immensely proud of my appointment at the Sports and Culture Attache for the Central African Republic."
Arbuthnot Latham & Co had no immediate comment on Becker's move.
The deputy foreign minister of the former French colony and one of the world's poorest and unstable countries, offered little support for Becker.
"No diplomat can avail himself of his immunity in the face of his own turpitude," Chancel Sokode told Reuters by phone. "He cannot brandish his immunity in this case to shirk his responsibilities."
Central African Republic has suffered a string of bloody political crises since former president Francois Bozize seized power in a 2003 military coup.
Violence erupted again in 2013 when mainly Muslim Seleka rebels ousted Bozize, prompting reprisals from mostly Christian militias.
A UN report last year said many of the incidents of rape, murder, torture and looting by various groups and governments from 2003-2015 could constitute crimes against humanity.
Becker has appointed human rights lawyer Ben Emmerson to handle his claim. Emmerson has previously represented Wikileaks founder Julian Assange as he contested his extradition to Sweden, and the wife of ex-KGB agent Alexander Litvinenko, who was murdered in London in 2006.
(Reporting by Alistair Smout in London and Crispin Dembassa Kette in Bangui; Editing by Edward McAllister, Matthew Mpoke Bigg and David Evans)
