The civil rights leader said Saturday that black New Yorkers "are not going to live in a town where our money is considered suspect and everyone else's money is respected."
Two black Barneys New York customers, Trayon Christian and Kayla Phillips, said this week they were detained by police after making expensive purchases.
Christian sued Barneys, saying he was accused of fraud after using his debit card to buy a $349 Ferragamo belt in April.
Barneys said Thursday it had retained a civil rights expert to help review its procedures.
Sharpton vowed to put shopping at Barneys "on hold" if the retailer fails to respond adequately to the allegations.