Rome, February 14 - Democratic Party (PD) leader and ex-premier Matteo Renzi on Wednesday warned against voting for the centre right saying it could lead to a "spread tax". Renzi was referring to the 2011 crisis that toppled Silvio Berlusconi's most recent government, when Italy looked in danger of suffering a Greek-style financial meltdown with its bond spread soaring. "Those proposing a flat tax, led us to the (soaring) spread," Renzi said at an event organized by retailers' association Confcommercio ahead of the March 4 general election. "There is no flat tax but a spread tax. Those who make unachievable proposals will put you in trouble".