The 29-year-old Brazilian player has yet to comment on the accusations, which relate to image payments that the Spanish authorities say should have been disclosed as income.
It is the second time the player has come under investigation in Spain.
Prosecutors are expected to argue Marcelo abused a convention in 2013 allowing highly paid stars to pay image rights revenues into off shore companies at a lower rate of tax.
The line will be familiar to fellow players Messi, Javier Mascherano and Ricardo Carvalho who have been convicted in similar prosecutions.
Portugal and Real striker Ronaldo is also under investigation and Manchester United manager José Mourinho is accused of irregularities while he was Real Madrid coach from 2011 to 2012.
Mourinho and Ronaldo deny any wrong doing.