The 'American Pie' star, 37, allegedly shouted at store employees at All Saints when she was refused a discount.
Eyewitnesses said she was screaming before she was escorted out by security.
Reid was shopping for an outfit to wear to the Coachella music festival when she grew angry with All Saints employees for being asked to pay full price.
She "demanded a discount," claiming she deserved it because of her fame.
Her spokesperson said Reid gets a discount with the chain in the U.K. and in Paris because Reid is "a walking billboard for them."
"She gets photographed, so they give her huge hook-ups. We told them we get a discount, and they said they'd email the press team," her spokesperson said.
The spokesperson also denied claims that Reid was drunk while in the store. Staff at the store checked to see whether they could give her a discount. She left without purchasing anything when they said they could not.