Lula was briefly detained and questioned on Saturday over the seaside home in connection with the massive Petrobras corruption and bribery scandal.
Prosecutors said Lula was targeted as part of the Operation Car Wash investigation into a sprawling embezzlement and bribery conspiracy.
The corruption scandal, which has already seen a Who's Who of Brazilian politicians and businessmen face charges, is believed to be the biggest ever in Brazil.
Lula was not arrested, but held for questioning over alleged "favours" received from corrupt construction companies implicated in a kickback scheme, prosecutors said.
"There is evidence that former President Lula received assets arising from the Petrobras scheme through the allocation and renovation of a triplex apartment and a site in Atibaia," prosecutors said last week.
- AFP, AP