"You can't hurt working-class people more when your policies target those who give you your jobs and they stop you from getting a pay increase," he said.
"We've seen a lot of that during the Obama administration and what did we have? We had low growth and flat wages."
On Wednesday, de Blasio -- the mayor of New York City -- told Fox News' Sean Hannity he plans to tax those making more than $2 million per year at as much as 70 percent.
De Blasio claimed former Presidents Dwight D. Eisenhower and John F. Kennedy taxed the wealthy at similar rates.
In response, Fleischer told host Neil Cavuto that Kennedy later worked toward cutting the tax rate, though the decrease did not go into effect until after President Lyndon Johnson entered the White House following the Massachusetts Democrat's assassination.
Regarding Yang, Fleischer said he would consider taking a closer look at the $12,000 per year stipend if, in exchange, all welfare programs outside of disability and the like were sunsetted.
"I find the universal income intriguing," he said.
Earlier this year, Yang claimed in an interview his proposal will encourage citizens to work.
Yang told TMZ that the plan is necessary to help American workers whose jobs have become automized. When asked if giving the dividend would incentivize workers, he cited the “Alaska Permanent Fund,” which was established in 1976 and pays residents a dividend from the state’s mineral revenue.
Fox News' Stephen Sorace contributed to this report.