A South African court has seized two luxury homes registered in the name of Teodorin Nguema Obiang, the son of the president of Equatorial Guinea.
President Obiang has ruled his country since 1979
Lawyers acting for a South African businessman, George Ehlers, are trying to recover $7m allegedly owed to him by the government for building work.
They say Mr Ehlers had to flee the country after attacks on his workers.
Equatorial Guinea's elite have amassed personal fortunes from oil revenues while most citizens live on $1 a day.
Mr Ehlers's attorney was quoted as saying the court action followed numerous efforts to secure payment for construction and engineering work he completed for the Equatorial Guinea government on the island of Annabon.
The houses are in Clifton and Constantia, two of Cape Town's most expensive suburbs, and have a combined value of about 50m rand ($9m).
The Clifton house is on a property that borders on a fashionable beach, with uninterrupted views over the Atlantic Ocean.
The Constantia home is close to the former residence of Sir Mark Thatcher, who was fined and received a suspended prison sentence last year over his part in an alleged coup plot in Equatorial Guinea.
In 2004, a US Senate investigation discovered that Equatorial Guinea President Obiang Nguema and members of his family were the signatories to accounts at Riggs Bank in the US which had received millions of dollars in revenues from the central African country's oil wells.
The investigation was carried out to try to assess whether American financial institutions were implementing anti-money laundering regulations put in place in the US since the attacks in Washington and New York on 11 September 2001.